Constipation in the elderly.

Constipation affects as many as 26 percent of elderly men and 34 percent of elderly women and is a problem that has been related to diminished perception of quality of life. Constipation may be the sign of a serious problem such as a mass lesion, the manifestation of a systemic disorder such as hypothyroidism or a side effect of medications such as narcotic analgesics. The patient with constipation should be questioned about fluid and food intake, medications, supplements and homeopathic remedies. The physical examination may reveal local masses or thrombosed hemorrhoids, which may be contributing to the constipation. Visual inspection of the colon is useful when no obvious cause of constipation can be determined. Treatment should address the underlying abnormality. The chronic use of certain treatments, such as laxatives, should be avoided. First-line therapy should include bowel retraining, increased dietary fiber and fluid intake, and exercise when possible. Laxatives, stool softeners and nonabsorbable solutions may be needed in some patients with chronic constipation.

The diagnostic utility of HASTE MRI in the evaluation of acute cholecystitis. Half-Fourier acquisition single-shot turbo SE.

PURPOSE: The purpose of this study was twofold: (a) to determine the significance of high signal intensity surrounding the gallbladder as seen on T2-weighted HASTE (half-Fourier acquisition single shot turbo SE) MR images in patients with acute cholecystitis and (b) to determine the sensitivity of T2-weighted HASTE MR images in detecting gallbladder and common bile duct (CBD) calculi in patients with acute cholecystitis. METHOD: Seventy-two patients with a suspicion of acute cholecystitis were referred for HASTE MRI over a 2 year period. Forty-one patients underwent MRI after sonography and the remaining 31 patients before sonography. MR images were independently evaluated for the presence of MR pericholecystic high signal and gallbladder and CBD calculi. Findings were correlated with results obtained at sonography and at surgery. RESULTS: Of the 72 patients imaged with HASTE MRI, 55 had cholecystitis based on clinical, sonographic, and/or surgical findings. Of these, 45 had acute and 10 had chronic cholecystitis. HASTE MRI demonstrated MR pericholecystic high signal in 41 of 45 (91%) of the patients with acute cholecystitis. The sensitivity of HASTE MRI in diagnosing acute cholecystitis was 91%. The specificity was 79%. The positive predictive value was 87%, the negative predictive value was 85%, and the overall accuracy of the test was 89%. Gallbladder stones were seen by HASTE MRI in 38 of 41 (93%) of patients with acute calculus cholecystitis demonstrated at sonography. CBD stones were demonstrated by HASTE MRI in seven of nine (78%) patients and by sonography in five of nine (56%) patients with documented choledocholithiasis on conventional cholangiography. CONCLUSION: HASTE MRI has a high degree of accuracy in diagnosing acute cholecystitis based on the single finding of pericholecystic MR high signal. A similar level of accuracy is demonstrated in detecting gallbladder stones. Biliary duct calculi are detected with even greater accuracy than with sonography in patients with acute cholecystitis. Invasive preoperative endoscopic retrograde cholangiography may therefore be limited to only those patients with acute cholecystitis and CBD stones demonstrated on HASTE MRI. These features make HASTE MRI and ideal imaging modality in the initial evaluation of acute biliary pain and may ultimately replace sonography in the preoperative evaluation of acute cholecystitis.

Update on obesity treatment.

Although the formula for weight control is a simple matter, namely ensure that calories consumed equals calories expended, its implementation is a source of great frustration for an estimated 85 million Americans. This results in an estimated 40 billion dollars spent each year in health and related treatment costs. This review outlines the epidemiology, health consequences, and treatment of obesity with an emphasis on newer developments in our understanding of the etiology of obesity and its treatment.

Fast MR imaging and the detection of small-bowel obstruction.

OBJECTIVE: Our aim was to determine whether fast MR imaging using the half-Fourier acquisition single-shot turbo spin-echo (HASTE) MR sequence is accurate for diagnosis of small-bowel obstruction. MATERIALS AND METHODS: Forty-three nonconsecutive patients with suspected small-bowel obstruction were evaluated with HASTE MR imaging during a 12-month period. Images were retrospectively assessed for the presence, level, and cause of bowel obstruction. Data were compared with results of conventional radiography and findings at surgery when available. RESULTS: Of the 43 patients imaged, 29 patients had small-bowel obstruction revealed by unenhanced or contrast-enhanced radiography or by CT. Surgical confirmation was available in 21 patients. Small-bowel obstruction was shown by HASTE MR imaging in 26 (90%) of these 29 patients. HASTE MR images showed the correct level of obstruction in 19 (73%) of the 26 patients and showed the cause of obstruction in 13 (50%) of the 26 patients. CONCLUSION: With a high degree of accuracy, HASTE MR imaging can show the presence and level of small-bowel obstruction.

Gastric volvulus: an old disease process with some new twists.

Gastric volvulus has been described in the medical literature for centuries. The acute presentation of gastric volvulus is dramatic and not often missed, and it is this type that is usually quoted in the literature and case citations. The subacute or chronic type, however, is frequently not recognized early in its presentation because it is accompanied by vague and nonspecific symptomatology suggestive of other abdominal processes. We review the classification, diagnosis, and treatments of gastric volvulus and highlight the significance of the chronic volvulus presentation through case descriptions, including endoscopic and radiographic features.

Rapid heparin anticoagulation: use of a weight-based nomogram.

The rapidity with which heparin anticoagulation is achieved is essential to a positive clinical outcome in patients with deep venous thrombosis or pulmonary embolus. However, adequate anticoagulation is frequently not achieved, either as a result of dosing regimens that do not take heparin kinetics into account or because of clinicians' wariness of possible hemorrhagic complications associated with elevated activated activated partial thromboplastin times. Obese patients are at particularly greater risk for subtherapeutic heparin dosing because their pharmacokinetic volumes of distribution differ from those in nonobese patients. Traditional empiric heparin dosing schemes may have pitfalls; methods that take into account the patient's weight are more likely to allow rapid anticoagulation. A nomogram that uses pharmacokinetic and volume of distribution principles to predict therapeutic levels of anticoagulation is presented.

Neuropathology of herpes simplex virus encephalitis in a rat seizure model.

Herpes simplex virus type 1 (HSV-1) is the cause of a serious and often fatal encephalitis. Patients who survive herpes simplex encephalitis (HSE) experience behavioral abnormalities including profound cognitive dysfunctions. We have developed a rat model of acute HSE to investigate the cognitive impairments caused by HSV-1 central nervous system (CNS) infection. Following intranasal inoculation of Lewis rats with a neurovirulent strain of HSV-1, animals shed virus in both ocular and nasal secretions and developed clinical signs of infection, including partial complex motor seizures that eventually generalized. Homogenization assays demonstrated infectious virus in the trigeminal ganglia, olfactory bulbs, and the piriform and entorhinal cortices. Histopathological assessment revealed inflammatory and hemorrhagic lesions in the trigeminal ganglia, olfactory bulbs, amygdala, hippocampus, the piriform and entorhinal cortices, and the spinal trigeminal nuclei. Viral antigens and nucleic acids were also detected within these structures by immunofluorescence microscopy and in situ hybridization, respectively. Viral-induced astrocytic hypertrophy in the CNS was demonstrated by glial fibrillary acidic protein immunoreactivity. Together, these results indicate that HSV-1 has the ability to invade, replicate, and induce site-specific CNS damage in the Lewis rat.

Spread of herpes simplex virus type 1 in the central nervous system during experimentally reactivated encephalitis.

Because many of the features of reactivated herpes simplex virus type 1 (HSV-1) central nervous systems (CNS) infections in vivo are incompletely understood, we used an animal model to study the development of the morphological, ultrastructural, radiological and immunological changes which occurred during acute and experimentally reactivated diseases. Rabbits were intranasally inoculated with HSV-1, and their latent trigeminal ganglionic and CNS infections were reactivated by intravenous injection of cyclophosphamide and dexamethasone. Technetium brain scans were performed to localize areas of blood-brain barrier breakdown, and cerebrospinal fluid (CSF) was analysed for IgG content by radial immunodiffusion assays. Nervous system tissues were studied by in situ hybridization and by immunofluorescent, light and electron microscopic techniques. Diffuse uptake of technetium was observed as HSV-1 spread transsynaptically into the brain during the acute phase of infection, and viral antigens and nucleic acids were detected in both the CNS olfactory and trigeminal systems. During latency, viral RNA was detected in the nuclei of neurons within the CNS olfactory cerebral and entorhinal cortices, indicating that HSV-1 became latent within the same CNS structures that were involved during the acute phase of infection. Following drug-induced reactivation, the brain scans revealed a more focal breakdown of the blood-brain barrier, and both neurons and neuronal processes in the entorhinal and olfactory cortices contained viral nucleic acids which correlated with the ultrastructural presence of HSV-1 virions. During the reactivated phase of infection a marked increase in the CSF IgG index occurred without an increase in the CSF: serum albumen ratio indicating a prompt intrathecal response in infected rabbits as compared to controls. To some extent, the CSF IgG index reflected the degree of histopathological damage.

Comparative effect of microwaves and boiling on the denaturation of DNA.

The effect of heat and microwave denaturation of small volumes of double-stranded plasmid DNA has been compared. Samples of intact plasmid DNA had plasmid DNA linearized by digestion with EcoRI were conventionally denatured in a boiling water bath or denatured by 2450 MHz of microwave energy for 0-300 s. Heat denaturation for periods longer than 120 s caused breakdown of linearized plasmid DNA; however, microwave denaturation for 10-300 s caused no apparent degradation of linearized DNA. Breakdown of DNA forms II and III was noted in plasmid DNA subjected to 300 s of either heat or microwave denaturation but breakdown of forms II and III occurred more quickly with heat than with microwave treatment. Microwave treatment was also found to be better than heat to denature 32P-labeled DNA probes subsequently used to detect homologous DNA samples immobilized on nitrocellulose filters. A microwave-treated 32P-labeled DNA probe was able to hybridize to DNA samples 20 times more dilute than a heat-treated 32P-labeled DNA probe. Depending on the form of DNA to be analyzed, these results indicate that small volumes of DNA solutions and radiolabeled DNA probes can be effectively denatured in a conventional microwave oven.

Porphyrin-laser photodynamic induction of focal brain necrosis.

A noninvasive photodynamic method has been developed to produce focal brain necrosis using porphyrin activated in vivo with laser light. After peripheral injection of the photosensitive porphyrin derivative, Photofrin I, mice were irradiated on the posterior lateral aspect of the head through the intact depilated scalp with 632 nm argon-dye laser light. Animals were studied at one, two and seven days after irradiation. Blood-brain barrier damage was detected by the intravenous injection of Evans blue, horseradish peroxidase and heterologous immunoglobulins. At one and two days after irradiation, the lesions were characterized by extravasation of immunoglobulin and Evans blue, and by edema, ischemia and infiltration by monocytes. On the seventh day after irradiation, the lesion was smaller than it had been two days after irradiation, and had reactive changes at its edges and coagulative necrosis at its center. Extravasation of Evans blue and immunoglobulin was markedly reduced by the seventh day after irradiation, but uptake of horseradish peroxidase by macrophages located at the periphery of the lesion was evident.

Pulmonary persistence of Haemophilus somnus in the presence of specific antibody.

Chronic experimental Haemophilus somnus pneumonia was produced in five 8- to 12-week-old calves to investigate host-parasite relationships in the respiratory tract. Calves were depressed and pyrexic and coughed intermittently for 3 days and then recovered except for sporadic coughing. Bacteria persisted in the lung for 6 to 10 weeks or more. Immunoglobulin G1 (IgG1), IgG2, and IgM but no IgA antibodies specific for H. somnus were detected in serum. Bronchoalveolar lavage samples contained detectable IgG1, IgG2, IgM, and IgA antibodies specific for H. somnus throughout most of the experiment. The kinetics of the isotypic antibody response against H. somnus in serum and bronchoalveolar lavage fluids differed, suggesting that both local and systemic antibody responses had occurred. Persistence of pulmonary infection for 10 weeks or more in the presence of antibody may be due to an inappropriate distribution of isotypes, toxicity of H. somnus for bovine macrophages, and perhaps other factors. Three of the calves were challenged with a 10-fold-higher dose of H. somnus at 10 weeks after the original inoculation. Immunity against H. somnus was indicated by the rapid clearance of bacteria from the lungs and the presence of minimal pneumonia at necropsy 3 days after bacterial challenge.

Neurovirulence of two clonally related herpes simplex virus type 1 strains in a rabbit seizure model.

Herpes simplex virus type 1 (HSV-1) strains vary widely with regard to neurovirulence, but their tropism for specific central nervous system structures and their ability to induce seizures are poorly defined. We have used the clonally related +GC and -GC strains of HSV-1 to define the pathophysiological basis of neurovirulence in a rabbit model. Following intranasal inoculation, +GC infection was nearly uniformly fatal while -GC infection was asymptomatic. The +GC infected animals developed electroencephalographic (EEG) abnormalities which preceded severe motor seizures. Tropism of the +GC strain for specific CNS nerve centers and the expression of viral antigens within them correlated with its virulence. Although both viruses invaded and replicated within the brain, +GC replicated to slightly higher titers and expressed more abundant viral antigen than -GC. The relatively less efficient replication of -GC appeared to correlate with its temperature-sensitive phenotype in vitro. Both +GC and -GC antigens were found in cerebral cortical layers IV-VI, and in several central nervous system trigeminal and olfactory system structures. However, +GC spread more completely throughout the brain to involve the amygdala, nucleus accumbens, several brainstem nuclei and the locus ceruleus. The +GC antigens were also found in cerebral cortical layer I of animals that developed seizures. These results indicate that the ability of HSV-1 to induce electrophysiologic brain abnormalities is associated with its ability to replicate within specific brain nerve centers.

Sympathomimetics and exercise enhancement: all in the mind?

During the 1972 Olympic Games, a 16 year old American athlete was compelled to return a gold medal and was disqualified from further participation. Rick Demont had used a sympathomimetic drug (ephedrine) prior to competition for treatment of his asthma as prescribed by his physician. The present research was carried out to investigate whether the administration of a sympathomimetic drug enhances maximal performance in the normal healthy individual in terms of physiological and psychological processes? Ten subjects participated in a double-blind, cross-over, counterbalanced incremental cycle ergometer test on two different occasions, once after ingesting placebo, once after ingesting ephedrine. Repeated measures ANOVA's revealed no significant differences in any of the cardiopulmonary (VE, VO2, VCO2, RQ and AT), cardiovascular (HR, BP, O2 Pulse, RPP) and psychophysiological (RPE) variables between treatments. Findings in the current investigation suggest that no advantage is obtained with the use of sympathomimetic drugs to augment one's maximal aerobic capacity.

Severity of experimentally reactivated herpetic eye disease is related to the neurovirulence of the latent virus.

The authors examined the eye diseases produced during acute and experimentally reactivated infections of rabbits intranasally inoculated with high and low neurovirulent strains of herpes simplex virus, type-1 (HSV-1). Experimental reactivation of latent trigeminal ganglionic infection was accomplished by an injection of cyclophosphamide followed by one injection of dexamethasone the next day. Neither drug, when given as a single injection, reactivated latent HSV-1 infection. During acute and reactivated phases of high neurovirulent HSV-1 strain infection, many rabbits developed very severe conjunctivitis and keratitis. Some rabbits developed hemorrhagic corneal lesions, and a few became blind. Only a few rabbits with acute and reactivated low neurovirulent virus strain infections developed mild conjunctivitis. The high neurovirulent strain was recovered from tear film more frequently than the low neurovirulent strain during reactivated infections. By use of 3H-labelled DNA prepared from purified virus to probe trigeminal ganglionic tissues in situ, both strains of virus were found to establish ganglionic latency to about the same degree. Reactivation correlated with an increase in the amount of HSV-1 RNA per ganglionic neuron and a change in subcellular location. These studies indicate that the relative neurovirulence of the infecting strain determines the ease with which it can be reactivated from latency and the severity of the reactivated ocular disease produced.

Herpes simplex virus, type 1 invasion of the rabbit and mouse nervous systems revealed by in situ hybridization.

Using a 3H-labelled virion DNA probe applied to tissue sections, we have previously identified the precise microscopic anatomical location of herpes simplex virus (HSV) during the acute and latent stages of infection of the mouse trigeminal ganglia and central nervous system (CNS). In the present investigation, we compared the mouse and the rabbit with respect to their ability to support acute and latent infections of trigeminal ganglionic and central nervous system neurons. We found that HSV-1, strain F, produced acute and latent infection of trigeminal ganglion cells in both mice and rabbits; however, lower levels of HSV-1 RNA were expressed in rabbit neurons as compared to mouse neurons, and many fewer neurons of the rabbit supported an acute infection than in the mouse. Studies of the trigeminal system within the CNS revealed that HSV-1 established latency more readily in the mouse than in the rabbit. The histopathology observed in acutely infected rabbit brain was less intense and less widespread than in mouse brain.

Production of encephalitis restricted to the temporal lobes by experimental reactivation of herpes simplex virus.

A model was developed in which reactivation of latent infections with herpes simplex virus type 1 was induced in trigeminal ganglia and central nervous system olfactory centers of rabbits by administration of cyclophosphamide and dexamethasone. Latent infections were reactivated at a significantly higher frequency in rabbits infected with a highly virulent strain of virus than in those infected with a strain of lower neurovirulence. Electroencephalographic abnormalities that were largely confined to the posterior lateral cerebral hemispheres and corresponding inflammatory lesions were seen in rabbits acutely infected with the highly virulent strain, whereas no brain electrical abnormalities and only mild inflammatory lesions were seen in rabbits acutely infected with the strain of low neurovirulence. Reactivation of the highly neurovirulent strain produced focal brain necrosis restricted to the temporal lobes, which was similar to the disease produced in humans and which correlated with progressive worsening of brain electrical abnormalities.

Effect of diet upon ventilation and effort perception during a physical stressor.

The present research explored the effects of a high and low carbohydrate diet on ratings of perceived exertion (RPE) during a 10 minute bicycle ergometer test at high physical work capacity (70% of maximum aerobic capacity). Twelve female student volunteers participated and were randomly assigned the order of diet treatments in which they served as their own control and/or experimental group. Following each dietary regimen, subjects were instructed to pedal the bicycle ergometer for ten minutes at an intensity of 70% of their maximum capability. Throughout the cycling protocol, RPE scores were recorded at 2, 4, 6, 8, and 10 minutes; in addition expiratory gases were collected and analyzed by a computerized indirect calorimetry system. Results in the current investigation indicated that an increased carbohydrate intake resulted in an "ergogenic" or "work-producing" effect by attenuating the metabolic acidosis, possibly diminishing the sensations of the central cardiopulmonary effort, further attenuating the psychophysiological perceptions of effort. Conversely, ingestion of a low carbohydrate diet resulted in accentuation of the ventilatory drive eliciting higher signals of exertion during dynamic exercise.

Maximal work capacity in prepubescent obese and nonobese females.

Measurements of cardiorespiratory function during an incremental treadmill test were compared in 15 obese (OB) prepubescent girls, 7 to 12 years old, and in 15 age-matched, nonobese (NOB) controls. Open circuit calorimetry was used for data collection during the progressive work test. Maximal oxygen consumption indexed for weight was significantly lower in the obese group of girls (23.0 +/- 3.9 ml/kg/min) than in the nonobese controls (36.7 +/- 0.9 ml/kg/min). In addition, exercise tolerance was longer in the nonobese group, albeit not statistically significant. In conclusion, diminished cardiopulmonary performance and attenuated exercise tolerance in prepubescent obese females in the current investigation seemed to be influenced by excess body weight.

Adaptation to maximal effort: genetics vs. environment. A case history.

An individual's functional ability in physiological responsiveness is thought to be an interaction between his heredity and his environment. This hypothesis was tested to determine if different extragenetic influences would alter functional adaptability in a set of MZ triplets. After a 3-month aerobic physical fitness training program varying only in frequency measured values for the triplets' maximum oxygen consumption (MaxVo2) were 59.1, 44.5, and 57.8 ml/min/kg, as compared to pretreatment values of 45.2, 45.1, and 49.1 ml/min/kg respectively. These results clearly indicate intrapair differences in functional adaptability, stemming from difference in the training frequency program. The split-triplet design of this study indicates that environmental factors contribute substantially to the intrapair variance found among MZ siblings. Data extrapolation suggests that environmental stimulation of sufficient magnitude is likely to alter the functional adaptability in the individual set by his genotype.

Personality and self-motivation during biochemical fatigue.

The present study was conducted to determine whether females exhibiting the Type A behavior pattern would exert greater effort and work to higher levels of physiological fatigue in a self-motivated ergometer test. Twenty female subjects, half of them Type A and the other half Type B, were administered an incremental ergometer test to determine their peak oxygen consumption value. On the first experimental session no experimenter encouragement was given to the subjects. Consequently the test measured physical motivation levels. During a second laboratory session, each subject was continuously encouraged by the experimenter to maintain exercising until she was truly incapable of further work. The highest rate of oxygen extraction during this latter session was considered the subject's maximum oxygen consumption (i.e., VO2 max). Type A and B subjects were compared in the nonmotivated testing session (experimental session 1) to their "true" individual capacities (maximum oxygen consumption demonstrated in experimental session 2). ANOVAs indicated no significant differences in self-initiated competitive behavior during a physical stressor.