Influence of microcatheter length on flow rates of disposable infusion kits.

BACKGROUND AND OBJECTIVE: Continuous spinal analgesia (CSA) offers considerable pain relief, and has been used in various procedures such as for surgery and cancer pain control. In Japan, portable and disposable infusion kits are increasingly employed for continuous epidural analgesia and CSA. In CSA, the use of a microcatheter is expected to reduce the incidence of spinal headache previously encountered with larger catheters. However, the flow rate of disposable infusion kits is reduced when used in conjunction with a microcatheter. METHODS: This study aimed to investigate the influence of catheter length on the flow rate of two different devices: 20- or 91-cm 28-G microcatheters connected to balloon- or syringe-type infusion pumps were examined (50 mL, 1 mL h(-1)). There were four groups each of 10 experiments: Group A: balloon-type infuser, 91 cm catheter; Group B: balloon-type infuser, 20 cm catheter; Group C: syringe-type infuser, 91 cm catheter; Group D: syringe-type infuser, 20 cm catheter. RESULTS: The mean flow rate in Group A was significantly less than that in Group B and the mean flow rate in Group C was significantly less than Group D (P < 0.05). CONCLUSION: These results indicated that the use of a shorter microcatheter achieves a better flow rate during CSA.

Aseptic meningitis during combined continuous spinal and epidural analgesia.

Continuous spinal analgesia (CSA) offers considerable advantages: (1) it requires 10% of the local anesthetic; (2) it may be instituted after patient positioning, thus minimizing the potential for cardiovascular instability; and (3) with low doses of dilute short-acting local anesthetic, the recovery period is shortened (1). Continuous spinal analgesia has been used for various procedures such as surgery and cancer pain control. However, CSA has not gained wide popularity because of its possible complications, such as headache, nerve injury, infection and accidental removal or migration of the catheter. Although real possibilities, these complications have been rarely documented. We describe an episode of aseptic meningitis during combined CSA and EA.

Preoperative blood pressure and catecholamines related to hypothermia during general anesthesia.

BACKGROUND: We previously demonstrated that preoperative blood pressure values affect intraoperative hypothermia during general anesthesia. We hypothesized that increased catecholamine secretion could be responsible for the relationship between preoperative blood pressure and hypothermia. METHODS: To evaluate the effect of preoperative systolic blood pressure (SBP) and plasma catecholamine levels on core temperature during general anesthesia, 40 male patients who were scheduled for open abdominal surgery were allocated to two groups: those whose preoperative SBP was 140 mmHg or greater (high SBP group, n = 20), and those whose SBP was less than 140 mmHg (normal SBP group, n = 20). Anesthesia was maintained with 0.4% isoflurane and opioids. RESULTS: The average age, height, and weight of the patients in the two groups did not differ. Preoperative SBP, mean blood pressure, diastolic blood pressure and heart rate in the high SBP group were significantly higher than those in the normal SBP group. Plasma norepinephrine concentrations in the high SBP group were significantly greater than those in the normal SBP group before and 1 h after the induction of anesthesia. Tympanic membrane temperatures in the normal SBP group started to decline further just after the induction of anesthesia, more so than that in the high SBP group. The vasoconstriction threshold in the normal SBP group was significantly lower than that in the high SBP group. CONCLUSION: These results suggest that the higher levels of preoperative catecholamine secretion contributed to the lesser degree of intraoperative hypothermia observed in the high SBP group.

Spinal cord injury in a child caused by an accidental dural puncture with a single-shot thoracic epidural needle.

IMPLICATIONS: A child experienced a spinal cord injury by an accidental dural puncture during thoracic epidural anesthesia. A magnetic resonance image was used for diagnosis and treatment.

Preoperative risk factors of intraoperative hypothermia in major surgery under general anesthesia.

UNLABELLED: Preoperative factors, such as age and body habitus, affect intraoperative hypothermia during general anesthesia. In a preliminary study, we developed a logistic model to retrospectively evaluate predictors of intraoperative hypothermia in patients who received major surgery. The following factors were selected to develop the model: Z = -15.014 + 0.097 x (Age) + 0.263 x (Height) - 0.323 x (Weight) - 0.055 x (Preoperative systolic blood pressure) - 0.121 x (Preoperative heart rate). By using this model, the probability of hypothermia can be estimated by applying the following formula: Probability = 1/(1 + e(-)(Z)). If an estimated probability of hypothermia was >0.5, the sensibility of prediction was 81.5% and the specificity was 83%. In the second study, the model was applied prospectively to other patients, and the validity of the logistic model was evaluated. The core temperature showed a significant decrease in patients with a probability >0.7, who were predicted to be hypothermic, and their thermoregulatory vasoconstriction threshold also showed a significant decrease, compared with the patients with a probability <==0.3, who were predicted to be normothermic. We concluded that intraoperative hypothermia could be predicted from preoperative characteristics such as age, height, weight, systolic blood pressure, and heart rate. IMPLICATIONS: Increases in age and height and decreases in weight systolic blood pressure and heart rate are major preoperative risk factors of intraoperative hypothermia during major surgery.

Role of blood volume in the age-associated decline in peak oxygen uptake in humans.

It has been reported that maximal oxygen uptake (VO(2 max)) is linearly correlated with blood volume (BV) in young people and that there is a reduction in VO(2 max) with aging. To examine the involvement of BV in the reduction of VO(2 max), we used an incremental cycle ergometer protocol in a semi-recumbent position to determine the relationship between peak oxygen uptake (VO(2 peak)) and BV in older subjects (69.1 +/- 1.0 years; n = 22), then compared that relationship with that in young subjects (22.3 +/- 0.5 years; n = 31). In the present study, VO(2 peak) and BV were significantly lower in the older subjects, compared with those in the young subjects. A linear correlation was demonstrated between the VO(2 peak) and BV in both the older (r = 0.705; p < 0.001) and the young (r = 0.681; p < 0.001) subjects within the groups. However, an analysis of covariance with BV as a covariate revealed that VO(2 peak) at a given BV was smaller in the older subjects than in the young subjects (p < 0.001), i.e., graphically, the regression line determined for the older subjects showed a downward shift. The decreased peak heart rate as a result of aging (153 +/- 3 beats/min in the older vs. 189 +/- 2 beats/min in the young subjects) contributed partly to this downward shift. These results suggest that the BV is an important determinant factor for VO(2 peak), especially within an age group, and that the age-associated decline of VO(2 peak) is also, to a relatively larger degree, because of factors other than BV and heart rate.

Effects of near-infrared low-level laser irradiation on microcirculation.

BACKGROUND AND OBJECTIVE: Recently, there has been an increase in the clinical application of low-level laser irradiation (LLLI) in various fields. The present study was conducted to explore the effects of LLLI on microcirculation. STUDY DESIGN/MATERIAL AND METHODS: We investigated the effects of LLLI on rat mesenteric microcirculation in vivo, and on cytosolic calcium concentration ([Ca2+]i) in rat vascular smooth muscle cells (VSMCs) in vitro. RESULTS: LLLI caused potent dilation in the laser-irradiated arteriole, which led to marked increases in the arteriolar blood flow. The changes were partly attenuated in the initial phase by the superfusion of 15 microM L-NAME, but they were not affected by local denervation. Furthermore, LLLI caused a power-dependent decrease in [Ca2+]i in VSMCs. CONCLUSION: The circulatory changes observed seemed to be mediated largely by LLLI-induced reduction of [Ca2+]i in VSMCs, in addition to the involvement of NO in the initial phase.

Efficient transformation of the edible basidiomycete Lentinus edodes with a vector using a glyceraldehyde-3-phosphate dehydrogenase promoter to hygromycin B resistance.

To construct a vector for high-level expression of heterologous genes in Lentinus edodes, the L. edodes GPD promoter, which is expressed constitutively and strongly, was fused to a hygromycin B phosphotransferase gene (hph) derived from Escherichia coli as a selective marker. Using the resulting pLG-hph construct, L. edodes was efficiently transformed to hygromycin resistance by restriction enzyme-mediated integration (REMI). The restriction enzyme concentrations yielding the maximal numbers of transformants by the REMI method were 10 U per transformation in the case of BglII and 25-50 U in the case of HindIII. Southern analysis of the transformants indicated that some 50% of plasmid integrations were REMI-mediated events. These results indicate that pLG is a useful vector for transformation of L. edodes. Deletion analysis of the GPD promoter region suggested that the segment between positions -442 bp and -270 bp relative to the transcription start point may be essential for function.

Effect of an exercise-heat acclimation program on body fluid regulatory responses to dehydration in older men.

We examined if an exercise-heat acclimation program improves body fluid regulatory function in older subjects, as has been reported in younger subjects. Nine older (Old; 70 +/- 3 yr) and six younger (Young; 25 +/- 3 yr) male subjects participated in the study. Body fluid regulatory responses to an acute thermal dehydration challenge were examined before and after the 6-day acclimation session. Acute dehydration was produced by intermittent light exercise [4 bouts of 20-min exercise at 40% peak rate of oxygen consumption (VO(2 peak)) separated by 10 min rest] in the heat (36 degrees C; 40% relative humidity) followed by 30 min of recovery without fluid intake at 25 degrees C. During the 2-h rehydration period the subjects drank a carbohydrate-electrolyte solution ad libitum. In the preacclimation test, the Old lost approximately 0.8 kg during dehydration and recovered 31 +/- 4% of that loss during rehydration, whereas the Young lost approximately 1.2 kg and recovered 56 +/- 8% (P < 0.05, Young vs. Old). During the 6-day heat acclimation period all subjects performed the same exercise-heat exposure as in the dehydration period. Exercise-heat acclimation increased plasma volume by approximately 5% (P < 0.05) in Young subjects but not in Old. The body fluid loss during dehydration in the postacclimation test was similar to that in the preacclimation in Young and Old. The fractional recovery of lost fluid volume during rehydration increased in Young (by 80 +/- 9%; P < 0.05) but not in Old (by only 34 +/- 5%; NS). The improved recovery from dehydration in Young was mainly due to increased fluid intake with a small increase in the fluid retention fraction. The greater involuntary dehydration (greater fluid deficit) in Old was accompanied by reduced plasma vasopressin and aldosterone concentrations, renin activity, and subjective thirst rating (P < 0.05, Young vs. Old). Thus older people have reduced ability to facilitate body fluid regulatory function by exercise-heat acclimation, which might be involved in attenuation of the acclimation-induced increase in body fluid volume.

Isolation and characterization of the glyceraldehyde-3-phosphate dehydrogenase gene of Lentinus edodes.

The glyceraldehyde-3-phosphate dehydrogenase (GPD) gene of Lentinus edodes was isolated from a genomic DNA library and cDNA corresponding to this gene was isolated from a mycelium cDNA library. The L. edodes GPD gene was found to encode a 337-aa protein. By comparison of the cDNA and genomic DNA sequences, the presence of eight introns in the GPD gene was confirmed. The putative amino acid sequence of the L. edodes GPD gene product showed high similarity to those of other basidiomycetes. The results of Southern blot analyses suggested that only one copy of the GPD gene is present in the genome of L. edodes. The promoter region was found to contain a CT-rich stretch, two CAAT boxes and a consensus TATA box. In addition, the transcript of the GPD gene was found to be expressed constitutively and strongly. These results suggest that the promoter of the L. edodes GPD gene may be very useful as a component of transformation vectors.

Transformation of the edible basidiomycete Lentinus edodes by restriction enzyme-mediated integration of plasmid DNA.

We have used the restriction enzyme-mediated DNA integration (REMI) method to establish a transformation system in Lentinus edodes using the recombinant plasmid pLC1-hph, which contains the L. edodes transcriptional signals and an Escherichia coli hygromycin B phosphotransferase gene. Protoplasts of L. edodes were treated by the PEG transformation mixture containing 50 units of SalI, which cleaves pLC1-hph at a single site, yielding about 15 transformants per 2.5 micrograms of DNA. The conventional PEG transformation without SalI, however, yielded only 1.5 transformants per 25 micrograms of DNA. The optimal amount of SalI for increased transformation was 50 units. In the case of transformation with SphI, which cleaves the plasmid at one site, the optimal amount of the enzyme was 2.5 units. Southern blot analysis of the SphI-derived transformants suggested that 50% of the plasmid integrations were REMI events.

Diffusivity of oxygen in microvascular beds as determined from PO2 distribution maps.

Dynamic changes in the distribution of PO2 in the rat mesentery were measured to determine the O2 diffusion coefficient (DO2) and consumption rate (VO2). The distribution of PO2 was obtained in two-dimensional maps by microscopic fluorometry on the basis of oxygen quenching. The corresponding vasculature was also recorded on a video recorder to analyze the PO2 distribution consistent with the arrangement of the microvessels. Anesthetized rats breathing room air were subjected to 100% O2 ventilation to induce dynamic changes in PO2 distribution. We assumed a homogenous and constant VO2 in the tissue, and a one-dimensional diffusion equation was applied to simulate oxygen transport. The PO2 data corresponded very well to the theoretical curves, and calculated DO2 was 1.04 +/- 0.78 X 10(-5) cm2/s (mean +/- SD, n = 38) and VO2 was 8.2 +/- 3.9 x 10(-6) cm3 O2.cm-3 tissue.s-1 (n = 27) at 37 degrees C. However, PO2 values at points remote from the arterioles remained higher than the theoretical prediction.

A simple construction of dual-slit red cell velocimeter.

A simple method of building a dual-slit red cell velocimeter is introduced. The basis of this technique is to utilize the body of a 35-mm photomicrography camera as the photometric device, exactly centering a pair of highly sensitive photodiodes on the film plane of the camera. By this arrangement, the microvascular image can be accurately focused on the sensing windows of the photodiodes. Because this velocimeter is not based on videophotometry, it was possible to measure red cell velocity up to 30 mm/s in the benchmark test. The maximum red cell velocity actually measured in the rat mesenteric microvessels (6.0 to 48 microns in diam) was 9 mm/s.

In vivo visualization of oxygen transport in microvascular network.

Oxygen transport from the blood to the tissues is a diffusive process driven by the gradient of oxygen tension (PO2). We developed an oxygen-quenching fluorescent membrane that allowed visualization of the PO2 distribution near the microvessels as optical patterns on the membrane by epifluorescence microscopy. This membrane was highly gas permeable to allow PO2 measurement and was transparent enough to also permit observation of the microcirculation. In combination with a newly devised gastight chamber and a micropositioning system, this membrane technique made it possible to visualize the PO2 distribution in the rat mesenteric microvascular network under well-defined conditions. Our preliminary findings indicate that the oxygen distribution in the microvascular network is heterogeneous and suggest that there is considerable release of oxygen from the arterioles. The time lag of the system for tracking rapid PO2 changes in vitro was shown to be negligible, indicating that dynamic PO2 changes occurring in vivo can also be assessed. This technique should provide a novel tool for the study of oxygen transport and metabolism under normal and abnormal conditions.

A closed chamber for intravital microscopy of the rat mesentery under controlled oxygen tension and temperature.

An airtight and watertight closed chamber for intravital microscopy of the rat mesentery was developed. It incorporates an oxygen microelectrode and a thermistor for monitoring the local environment around the mesentery, as well as a heater for controlling the chamber temperature. This chamber provides an alternative to the superfusion method for intravital microscopy of the mesenteric microcirculation under circumstances where well-defined experimental conditions are required.

[Portal vein infusion therapy of the prevention of liver metastasis from colorectal carcinomas].

For patients who underwent curative resections for primary colorectal carcinomas, locally recurrent tumors and metastatic liver tumors, we applied portal vein infusion therapy to prevent further metastases to the liver. Following radical resection of the tumor, dissecting the umbilical vein from the falciform ligament made it possible to recanalize and insert a 18 G catheter into the portal vein. Intraportal chemotherapy (5-FU 750 mg/day) was carried out for the first 7 postoperative days. There were 17 patients who received this therapy, 10 with curative resection for the primary cancers, 1 with curative resection for the locally recurrent tumor and 7 with the curative resection for the metastatic liver tumors. The follow-up period is rather short (17 months) but no patients have had the liver metastases. So we suggest that this adjuvant liver infusion may reduce the liver metastases without any mortality or morbidity.

Self washout method for defecational complaints following low anterior rectal resection.

A self washout method was performed by ten patients who had defecational complaints following an anterior resection. A commercially available colostomy washout set was used for this procedure. When the patient sat down, the cone tip of the set was pressed into the anal canal by pushing the cone with the palm of the hand. The volume of water for irrigation used was 500 to 1000 ml and the subsequent defecation time was from 20 to 50 minutes. In all cases, the frequent urge to defecate disappeared and after normal defecational function had been recovered, the self washout was able to be discontinued.

[Long-term pathophysiological studies on loop ileostomy and ileoanal anastomosis].

Mucosal proctectomy with ileoanal anastomosis (IAA) had been performed on 37 patients with adenomatosis coli and 16 with ulcerative colitis between 1978 and 1987. These patients were followed up for a mean of 7.5 years. In 38 cases (73%), this procedure was completed by closure of loop ileostomy. The mean number of bowel movements per 24 hours was 6.0. Seven patients had occasional episodes of minor nocturnal soiling. The postoperative maximum resting anal pressure was the most important parameter reflecting clinical results and it rose from 72 to 92 cm of water during 5.3 year follow-up period after IAA. The pathophysiological studies on loop ileostomy and IAA were performed in these patients. Postoperative small bowel transit time evaluated by radioopaque markers was shortened. Daily output of water and sodium, and Na/K ratio in the ileal excreta increased and total counts of anaerobes in feces decreased. On the other hand, daily volume, Na/K ratio and PH of urine fell significantly. These phenomena were remarkable in patients who received loop ileostomy with about 60 cm defunctioning terminal ileum. These results indicate that it is necessary to maintain intestinal continuity in the ileal pouch-anal procedures.