Doppler ultrasound for the assessment of conservatively treated blunt splenic injuries: a prospective study.

INTRODUCTION: The type and need for follow-up of non-operatively managed blunt splenic injuries remain controversial. The use of Doppler ultrasound to identify post-traumatic splenic pseudoaneurysms, considered to be the main cause of "delayed" splenic rupture, has not been well described. PATIENTS AND METHODS: A 5-year prospective study was performed from 2004 to 2008. All patients with blunt splenic injury diagnosed with computerized tomography, who were treated non-operatively, were included in the study. Doppler ultrasound examination was performed 24-48 h post-injury. Consecutive Doppler ultrasound examinations were done on 7, 14 and 21 days post-injury for patients diagnosed with a splenic pseudoaneurysm. Demographic and clinical data were collected. Ambulatory follow-up continued for 4 weeks after hospital discharge. RESULTS: A total of 38 patients were enrolled in the study. Grading of splenic injury demonstrated 19 (50%) patients with Grade I, 16 (42%) with Grade II and 3 (8%) with Grade III injuries. Two patients (5%) had pseudoaneurysms. All pseudoaneurysms underwent complete resolution within 2 weeks after diagnosis. No patients received blood products, or had angio-embolization or surgery during the study period. All patients were found to be asymptomatic and stable at the 4-week follow-up. CONCLUSIONS: Doppler ultrasound can be an effective and a safe noninvasive modality for evaluation and follow-up of patients with blunt splenic injury. The utility and cost-effectiveness of routine surveillance requires further study.

Endoscopic sphincterotomy and temporary internal stenting for bile leaks following complex hepatic trauma.

BACKGROUND: Biliary leak secondary to blunt or penetrating hepatic trauma and damage to the intrahepatic biliary tree remains a challenging problem. The role and safety of endoscopic retrograde cholangiopancreatography (ERCP) and stenting in this setting were studied. METHODS: All trauma victims who developed a bile leak secondary to hepatic trauma were included. Bile leak was defined as the appearance of bile in a surgical wound or intra-abdominal drain after surgery, following percutaneous drainage of a perihepatic bile collection, or evidence of a leak on hepatobiliary scintigraphy. ERCP was performed within 24 h of diagnosis and included biliary sphincterotomy and internal stenting. Recovery was defined as cessation of leakage. RESULTS: Between 1996 and 2004, six patients with penetrating injuries and five with blunt abdominal injuries were treated according to the study protocol. Eight underwent surgery to control bleeding or for additional intra-abdominal injuries. All bile leaks resolved completely within 10 days of ERCP. One patient died from pulmonary sepsis; ten recovered without hepatobiliary sequelae. CONCLUSION: ERCP, biliary sphincterotomy and temporary internal stenting, together with percutaneous drainage of intra-abdominal or intrahepatic bile collections, represent a safe and effective strategy for the management of bile leaks following both blunt and penetrating hepatic trauma.

The impact of a resident's seniority on operative time and length of hospital stay for laparoscopic appendectomy: outcomes used to measure the resident's laparoscopic skills.

BACKGROUND: Laparoscopic appendectomy (LA) frequently is performed by residents during calls. This study aimed at evaluating residents' surgical skills using parameters of operating time, length of hospital stay (LOS), and conversion rate in correlation with the operating team's level of seniority. In addition, this study compared the operating time for LA with that for open appendectomy performed by the same teams, and identified deterministic factors that have an impact on such parameters. METHODS: All records of patients undergoing appendectomy performed by residents alone during a 32-month period were reviewed retrospectively. Eight residents were assigned to two levels of seniority: juniors 3 years (S). Operating time and LOS were compared between the three surgical teams, namely, J/J, J/S, and S/J as operating and assistant surgeons, respectively. Operating time, conversion rates, and LOS were compared for the same team combinations. RESULTS: Residents alone performed 341 (151 laparoscopic and 190 open) appendectomies during on-call hours. Four of the residents had been 3 years or less in residency (J), and four had been in residency more than 3 years (S). The overall mean operating time was 1.33 +/- 0.48 h for LA and 1.2 +/- 0.5 h for open appendectomy (p = 0.016). The operating time correlated with the level of training for both LA (J/J, 1.6 +/- 0.38 h; J/S, 1.41 +/- 0.37 h; S/J, 1. 25 +/- 0.4 h; p = 0.03, ANOVA) and open appendectomy (J/J, 1.53 +/- 0.89 h; J/S, 1.4 +/- 0.63 h; S/J, 0.86 +/- 0.45 h; p = 0.023, ANOVA). The mean LOS was 2.9 +/- 3.1 days for open appendectomy and 2.1 +/- 2.8 days for LA (p = 0.065), and was not different after operation by any of the teams (J/J, J/S, S/J) for either the open or the laparoscopic procedure. CONCLUSIONS: There is a distinct difference in the surgical skills of residents according to level of seniority, as primarily reflected by operating time. Laparoscopic appendectomy requires longer time to perform in a teaching setting, but the most deterministic factor that dictates operating time is the composition of the surgical team rather than the laparoscopic approach.

140 consecutive cases of minimally invasive, radio-guided parathyroidectomy: lessons learned and long-term results.

BACKGROUND: The advent of highly accurate parathyroid imaging and the ever-increasing trend towards minimally invasive procedures have changed considerably the surgical approach to the patient with primary hyperparathyroidism (PHPT) caused by a single parathyroid adenoma. This study analyzes the short- and longer-term results of 140 patients who underwent minimally invasive, radio-guided parathyroidectomy. METHODS: Demographic, clinical, and pre-operative imaging data, operative findings, and short- and long-term results of 140 consecutive patients operated within a 20 months period (8/1999-4/2002), were prospectively entered into a database. Immediate pre-operative sestamibi scintigraphy with skin marking of focal adenoma uptake were followed by intraoperative hand-held gamma probe for the removal of the parathyroid adenoma by unilateral minimal access surgery. Preoperative and surgical data were analyzed and correlated to outcomes, measured by success or failure to cure PHPT, associated morbidity and mortality, predictive value of localizing studies, and postoperative laboratory results in the immediate as well as long-term period. RESULTS: 140 patients, mean age: 55.1 +/- 14.1 years (range 19-88 years), female to male ratio 94:46 with PHPT proven by concomitantly elevated serum calcium and parathormone (PTH) levels, with a single adenoma identified by sestamibi single photon emission tomography (SPECT) scintigraphy and high-resolution sonography, underwent minimally invasive, radio-guided parathyroidectomy. Mean serum levels of preoperative calcium, phosphorus, and PTH were 11.6 +/- 0.8 mg/dL (range 9.1-14), 3.0 +/- 0.3 mg/dL, and 147.1 +/- 94.3 pg/mL (range 68-784), respectively. Overall, in 3 out of 140 patients (2.1%), focused, minimally invasive surgery failed to identify and remove the adenoma. Positive predictive value when both localizing modalities concurred was 99.2%. Positive predictive value of SPECT scan alone was 97.2%. Overall success rate was 97.8% (137/140). 24 hours postoperative mean serum calcium was 9.2 +/- 0.8 mg/dL and at 6 months mean serum calcium, phosphorus, and PTH were 9.4 +/- 1.06 mg/dL, 3.2 +/- 0.8 mg/dL, and 32.1 +/- 11.9 pg/mL, respectively (p = 0.0001). There was no mortality. In 2 patients (1.4%) there was transient vocal cord paresis and there were 8 instances of clinically significant hypocalcemia. In 3 cases (2.1%), a second adenoma manifested itself 9-14 months following surgery and was removed by minimal access procedure. CONCLUSIONS: Minimally invasive, radio-guided focused parathyroidectomy for a single adenoma is safe and effective in curing hyperparathyroidism with a 97% success rate. A second adenoma occurring in less than 3% may be successfully treated with a second minimal access operation. The combined positive predictive value of concurring sestamibi SPECT scintigraphy and sonography of 99.2% may increase success rate, and thus implementing this technique in patients with concurring sonography and scintigraphy may be advocated.

Pitfalls and complications with laparoscopic intraperitoneal expanded polytetrafluoroethylene patch repair of postoperative ventral hernia.

BACKGROUND: This study reviewed our experience with laparoscopic ventral postoperative (incisional) hernia repair. METHODS: Clinical data from the first 100 cases were analyzed retrospectively. RESULTS: Between 1997 and 2000, 64 women and 36 men (mean age, 58.4 +/- 13.6 years; range, 27-87 years) underwent laparoscopic hernioplasty. Hernias (mean diameter, 6.2 +/- 3.7 cm) were in a midline (74%), subcostal (10%), or other incision location, and were recurrent in 25%, of the patients. The mean operative time was 119 +/- 77 min. Extensive adhesiolysis was necessary in 37 cases. There was no mortality. The recorded complications included inadvertent enterotomies (n = 6), seromas (n = 11), prolonged ileus (n = 4), and prolonged fever (n = 3). Seven cases were converted; to repair accidental enterotomies (n = 4) due to difficult adhesiolysis (n = 2), or to control bleeding (n = 1). Six patients underwent reoperation because of enetric leak (n = 3) or bowel obstruction (n = 3). There were two documented recurrences (2%). The mean follow-up period was 19 months (range, 12-54 months). CONCLUSIONS: Laparoscopic intraperitoneal approach to postoperative ventral (incisional) hernia repair may be associated with significant complications and morbidity, which can be prevented in part by meticulous technique and liberal conversions. The justification of this procedure is the low recurrence rate, according to preliminary results.

Fibroadenoma of the breast: analysis of associated pathological entities--a different risk marker in different age groups for concurrent breast cancer.

BACKGROUND: Fibroadenoma, one of the most common benign breast lesions, has a characteristic age-specific incidence and is associated with other pathological entities in 50% of cases. The clinical or imaging diagnosis of fibroadenoma may be erroneous, and in some cases is found to be invasive cancer. The clustering of such entities, their correlation with age, and the risk of synchronous breast malignancy are uncertain. OBJECTIVE: To explore the possibility of any significant clustering of fibroadenoma-associated benign breast diseases and to assess the possible risk of concomitant breast cancer. METHODS: We analyzed the pathological results of 147 women undergoing excisional biopsies for fibroadenoma diagnosed pre-operatively either by clinical examination and imaging (n = 17) or by radiology alone (n = 30). The inter-relationships among all entities associated with fibroadenoma were studied by hierarchical cluster analysis. The correlation of the various pathologies with the risk of invasive breast cancer in relation to the patient's age was also evaluated. RESULTS: Fibroadenoma-associated pathologies were found in 48% of the cases: sclerosing adenosis (23%), duct ectasia (17.7%), apocrine metaplasia (15.6%), florid fibrocystic disease (12.9%), duct papillomatosis (11.6%), infiltrating duct carcinoma (5.4%), duct carcinoma in situ (3.4%), and 1 case of lobular carcinoma in situ (0.6%). An orderly internal hierarchy and three significant clusters emerged: a) epithelial apocrine metaplasia, duct ectasia and sclerosing adenosis (similarity coefficients 16.0, 11.0 and 8.0 respectively); b) papillomatosis, florid fibrocystic disease and calcifications (similarity coefficients of 6.0, 4.0 and 2.0 respectively); and c) infiltrating duct carcinoma and duct carcinoma in situ (similarity coefficients of 1.8 and 1.6 respectively). Seven of the eight patients with breast cancer were older than 40 years. CONCLUSIONS: In about half of the cases fibroadenoma was associated with other pathological entities clustered in an orderly hierarchy. The rarity of synchronous breast cancer in the younger age group and its more common association with fibroadenoma in the older age groups dictate a different approach to each. The finding of fibroadenoma in women older than 40 indicates the need for surgical excision.

Critical graft size in adult-to-adult living donor liver transplantation: impact of the recipient's disease.

The aim of this study is to analyze the impact of the recipient's disease severity on graft size requirements and outcome in adult-to-adult living donor liver transplantation. A limiting factor in adult-to-adult living donor liver transplantation has been adequacy of graft size. A minimal graft-recipient weight ratio (GRWR) of 0.8% to 1% has been suggested, without taking the recipient's disease into account. Forty adults underwent liver transplantation using left (n = 10; mean weight, 481 +/- 83 g) or right lobes (n = 30; mean weight, 845 +/- 182 g). We recorded graft survival, Child-Turcotte-Pugh score, and occurrence of small-for-size syndrome (poor bile production, prolonged postoperative prothrombin time, and cholestasis without ischemia markers). Small grafts were defined as GRWR of < or =0.85%. Large grafts were defined as GRWR greater than 0.85%. Six patients died within 6 months of transplantation (early patient survival rate, 85%); two patients died late of tumor recurrence. Among transplant recipients with normal liver function or Child's class A, there was no significant difference with the use of small (n = 6) or large (n = 9) grafts (graft survival rates, 83% v 88%, respectively; P =.65). Among patients with Child's class B or C, graft survival rates were 74% in recipients of large grafts (n = 19) and 33% in recipients of small grafts (n = 6; P =.023). Five of 6 patients with Child's class B or C who received small grafts developed small-for-size syndrome; 2 patients died (1 patient after retransplantation) and 3 patients survived (2 patients after retransplantation). Graft function and survival are influenced not only by graft size, but also by pretransplantation disease severity. GRWR as low as 0.6% can be used safely in patients without cirrhosis or in patients with Child's class A. Transplant recipients with Child's class B or C require a GRWR greater than 0.85% to avoid small-for-size syndrome and related complications.

Transepithelial intestinal excretion of ciprofloxacin in humans.

The excretion of ciprofloxacin in the small bowel was studied in 40 patients undergoing bowel surgery. Ciprofloxacin (200 mg) was administered iv, and intestinal samples were collected over a 120-min period. In ileal loops ciprofloxacin concentrations reached a peak of 4.0 mg/L, whereas in caecal fluid samples, concentrations were < 0.16 mg/L. Ciprofloxacin administered directly into the ileal and caecal loops did not result in measurable blood levels for 2 h. The results confirm that ciprofloxacin is selectively excreted into the small bowel.

Use of daclizumab as initial immunosuppression in liver transplant recipients with impaired renal function.

The addition of daclizumab (a human immunoglobulin G1 monoclonal antibody that blocks interleukin-2 receptors on T lymphocytes) to mycophenolate mofetil (MMF) and steroids is a new option for initial immunosuppression in patients undergoing liver transplantation (LT) with impaired renal function. We evaluated the efficacy and safety of daclizumab in preventing rejection in 25 patients with impaired kidney function undergoing LT. Patients with serum creatinine (Cr) levels greater than 2 mg/dL immediately before LT were administered initial immunosuppression with daclizumab, 1 mg/kg, in addition to MMF, 2 g/d, and methylprednisolone. Tacrolimus was added after kidney function improved (when Cr levels improved by >25% of initial value). Daclizumab-treated patients were compared retrospectively with 2 other groups of patients who underwent LT with kidney impairment (Cr > 2 mg/dL): 56 patients were administered OKT3 induction, and 48 patients were administered low-dose tacrolimus. The incidence of rejection and infection (bacterial, fungal, and viral), need for preoperative and postoperative dialysis, Cr level immediately post-LT and at 3 months, and graft and patient survival were analyzed. There was no difference among the groups in 3-month Cr levels or the incidence of rejection or fungal or viral infection. The daclizumab group had fewer bacterial infections (n = 13) than the tacrolimus group (n = 28) and significantly fewer than the OKT3 group (n = 58; P =.006). Only 1 patient (4%) in the daclizumab group required dialysis post-LT versus 13 patients in each of the other groups (OKT3, 23.21%; P <.05; tacrolimus, 27%). In the daclizumab group, 2-year patient and graft survival rates were statistically significant compared with the low-dose tacrolimus group (89% and 81% v 73% and 69%, respectively; P =.06). There were no side effects related to daclizumab use, and all patients tolerated the drug well. In patients with impaired renal function before LT, daclizumab-based initial immunosuppression can be used safely to reduce the risk for infection and need for dialysis post-LT, with improved long-term graft and patient survival.

A 67-year-old man with hepatitis C virus infection and a liver tumor.

A 67-year-old man with no known liver disease was found to have an incidental tumor in the right liver lobe. His serum liver enzyme and alphafetoprotein were within normal limits, but he was found to be reactive for anti-HCV. The tumor was an intrahepatic cholangiocarcinoma. Since the only risk factor in this patient was hepatitis C infection, this case appears to support the recently suggested role of hepatitis C virus in the development of intrahepatic cholangiocarcinoma.

Mechanisms of systemic hypertension during acute elevation of intraabdominal pressure.

INTRODUCTION: In previous studies we described mechanisms by which acute elevation of the intraabdominal pressure (IAP) induces intracranial hypertension (ICHTN). Here we sought to define the role of ICHTN in mediating systemic hypertension (HTN) during CO(2) pneumoperitoneum (PNP). METHODS: Six large animals (swine) were hyperventilated to buffer hypercarbia. Intracranial pressure (ICP) was monitored with a Camino intraparenchymal ICP monitoring system. A Foley catheter was introduced intracranially via a separate burr hole. At phase 1, changes in ICP, central venous pressure (CVP), and mean arterial pressure (MAP) were recorded during periods of CO(2) PNP at IAP levels of 15, 20, 25, and 30 mm Hg. At phase 2, ICHTN was produced directly by inflating the intracranial balloon to the same ICP levels that had been measured in phase 1 for each degree of IAP. CVP and MAP were recorded. Repeated measures analysis of variance was applied. RESULTS: At phase 1, the mean DeltaCVP, DeltaICP, and DeltaMAP increased relative to the degree of IAP (P = 0.0001, 0.0004, and 0.024, respectively). At phase 2, the increments in DeltaMAP were significant (P = 0.024) and in the same direction and amplitude as at phase 1. CONCLUSIONS: In this study, increasing the IAP with CO(2) PNP with a consequent increase of ICP and direct manipulation of the ICP produced a comparable systemic HTN. We believe that this further supports our hypothesis: Elevated IAP produces an immediate increase in the CVP, which impairs venous drainage from the central nervous system (CNS), increases the ICP, and initiates a CNS-mediated response and systemic HTN.

Hepatic epithelioid hemangioendothelioma: resection or transplantation, which and when?

Hepatic epithelioid hemangioendothelioma (HEHE) is a rare tumor with an unpredictable course and prognosis. The aim of this study is to describe our experience with liver resection, as well as transplantation, in the treatment of this tumor. We retrospectively analyzed the clinical features, pathological findings, and postoperative results in a series of 11 patients presenting between 1990 and 1998. Five patients (45%) presented with abdominal pain, 3 patients (27%) with jaundice and ascites, and the rest were asymptomatic. Computed tomography or magnetic resonance imaging showed localized lesions in 2 patients (18%) and multifocal disease in the others. Seven patients (64%) had extrahepatic lesions, detected either by preoperative imaging or discovered at exploration. Two resections of apparently localized lesions were followed by rapid and aggressive recurrence. Five patients were treated with transplantation, including 1 patient who had previously undergone resection. Of these 5 patients, 2 patients are currently free of detectable disease, 1 patient who had severe ascites and jaundice is now asymptomatic with stable extrahepatic lesions, and 2 patients (including 1 who had previously undergone a resection) died of tumor recurrence. One patient with advanced tumor died while waiting for transplantation. The remaining 4 patients are free of symptoms and have stable hepatic and extrahepatic disease. HEHE is nearly always multifocal, and our results with resection were dismal. Because of the unpredictable nature of the tumor, the indications for transplantation in patients without liver-related symptoms should be carefully evaluated. Nevertheless, extrahepatic disease should not be an absolute contraindication for liver transplantation in patients with severe liver dysfunction.

A 42-year-old woman with liver masses and long-term use of oral contraceptives.

A 42-year-old woman with a history of 25-year oral contraceptive use presented with abdominal pain and was found to have two exophytic liver masses. She had no known prior liver diseases, and her serum liver enzyme and AFP levels were normal. One of the masses was a hepatocellular adenoma and the other was a pigmented hepatocellular carcinoma. The exophytic appearance of both lesions was unusual. This case, once more, demonstrated the risk of hepatocellular adenomas to undergo malignant transformation. The reason for the brown pigment deposition in the hepatocellular carcinoma was not clear. The prognosis was expected to be excellent following complete surgical resection.

Causes of arterial hypertension and splachnic ischemia during acute elevations in intra-abdominal pressure with CO2 pneumoperitoneum: a complex central nervous system mediated response.

The application of laparoscopic technique has gained popularity in the past decade. Numerous studies have qualified and quantified the systemic impact of acutely elevated intra-abdominal pressure during pneumoperitoneum at time of laparoscopy. The major hemodynamic effects are increased central venous pressure, increased systemic vascular resistance and systemic hypertension. Reductions in splanchnic and renal blood flow have also been documented, but the clinical significance of these observations is not clear and required further investigation. In our previous work we demonstrated intracranial hypertension secondary to acute elevation in intra-abdominal pressure and described the pathophysiology. Elevated intra-abdominal pressure during induced pneumoperitomeum can serve as a basic model for other disease processes which are characterized by acute or chronic abdominal hypertension. Here we review the current literature and describe our own experience to suggest a unifying model, with emphasis on the key role of the central nervous system in mediating the systemic response to increased intra-abdominal pressure.

[Abdominal compartment syndrome].

Abdominal compartment syndrome refers to a complex of negative effects of intra-abdominal hypertension. Its most common cause is complicated abdominal trauma. The syndrome includes mainly hemodynamic and respiratory manifestations but may involve other systems as well. It may present as a life-threatening emergency in the multi-trauma patient. Awareness of the syndrome may enable the surgeon to take preventive measures or to diagnose it earlier and to treat it effectively. We describe a 21-year old man who developed this syndrome after multiple gunshot wounds, with severe liver injury. After 2 operations the typical manifestations of the syndrome were diagnosed. He was re-operated to release intra-abdominal hypertension and then slowly recovered.

Is the obstetric outcome of in vitro fertilized singleton gestations different from natural ones? A controlled study.

OBJECTIVE: To determine whether singleton IVF pregnancies carry adverse maternal or fetal outcome when compared with naturally conceived gestations. DESIGN: An analysis of the obstetric outcome of singleton IVF pregnancies in comparison with matched, naturally conceived singleton controls. SETTING: In vitro fertilization unit and obstetric service at a tertiary medical center. PATIENT(S): Two hundred sixty consecutive singleton IVF pregnancies and 260 naturally conceived singleton controls matched 1:1 for maternal age, parity, ethnic origin, and location and date of delivery. INTERVENTION(S): In vitro fertilization-ET. MAIN OUTCOME MEASURE(S): The rate of antenatal obstetric complications, nonvertex presentation, cesarean section, preterm labor, low birth weight, small and very small for gestational age, neonatal intensive care unit admissions, and perinatal mortality. RESULT(S): The rates of most antenatal complications were similar in both groups. Urinary tract infection was the only complication diagnosed significantly more frequently after IVF (7.3% versus 1.2%); however, the rates of severe urinary tract infection necessitating hospitalization were similar. The incidence of nonvertex presentation was also similar. The cesarean section rate was significantly higher among IVF patients (41.9% versus 15.5%). The rates of preterm labor, low birth weight, small and very small for gestational age, neonatal intensive care unit admissions, and perinatal mortality were comparable. CONCLUSION(S): When controlling for maternal age, parity, ethnic origin, and location and date of delivery, singleton IVF pregnancies do not carry an increased risk for prematurity, low birth weight, or maternal or fetal complications. Still, these pregnancies are associated with a high rate of cesarean sections.

[Surgical approach to benign cecal ulcer].

Benign cecal ulcer is a rare lesion, usually diagnosed during operation for suspected acute appendicitis or peritonitis of unknown origin. In the past, right hemicolectomy was recommended as the treatment of choice because of the difficulty in differentiating malignant lesions from benign cecal ulcers. However, in recent reports a more conservative approach has been suggested, consisting of selective colectomy followed by frozen section biopsy. This approach is aimed at preventing unnecessary excision of the colon and conserving the ileocecal valve. We present a 47-year-old woman operated for right lower quadrant peritonitis, believed to be due to acute appendicitis. On exploration, a biopsy-proven benign cecal ulcer was found and resected.

Personality core dynamics and drug preference.

The aim of this study is to investigate the possible link between Shoham's personality-core theory [1] and addiction to hard drugs. Basing ourselves on Kleinean premises, that the oral stage is critical in the formation of behavioural patterns, which are influential throughout life, we hypothesize that in the oral stage two opposing vectors, 'separation' and 'participation' are initiated. By 'participation' we refer to the identification of ego with an external object or symbol, and continuous tendency to lose the personal identity by fusion with this object or symbol. 'Separation' is the opposite vector and expresses ego's tendency to incorporate the external object or symbol. These vectors form two multidimensional personality axes, on which the different personality types and behavioral patterns can be anchored. This study aims at investigating the connection between these two vectors and drug addiction. We view drug addiction as a functional behaviour pattern, which brings the individual to a state of internal balance. Shoham's personality theory hypothesizes the derivation of behavioural patterns of different personality 'types', according to the strength of the two vector - the 'separant' and 'participant' types. It is hypothesized that the drug use and the experience gained by using the specific drug by different personality types will vary according to the prominence of the core personality vector. The potency of these vectors is related to an early oral (participant) or a later oral (separant) fixation.(ABSTRACT TRUNCATED AT 250 WORDS)