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Biomedical subjects

B R Pachter

Publications and source records attributed to B R Pachter.

At least 19 recordsLinked to original sources
PubMed1997

Cocaine-associated intestinal gangrene in a pregnant woman.

A 31-year-old pregnant woman who was an active cocaine abuser presented to our emergency department five times in 1 week for abdominal pain and vomiting. She continued to use cocaine regularly despite having abdominal pain. Her fifth admission was for seizures. There were no objective signs of peritoneal inflammation and the rectal guiac examination was repeatedly negative. The patient progressed to severe septic shock. Intraabdominal sepsis and/or bowel perforation was suspected. Exploratory laporatomy revealed gangrene and perforation of the small intestine and fecal peritonitis. She rapidly developed multiorgan failure and died. Gastrointestinal complications resulting from cocaine use are uncommon. Our case is unique in that the patient was pregnant, used cocaine by the intranasal route, and lacked objective signs of acute abdomen. Emergency physicians should be aware of the morbidity associated with the use of cocaine.

Adult↗
PubMed1997

Hemodynamic, electrocardiographic, metabolic, and hematologic abnormalities resulting from lithium intoxication. A case report.

The authors report a unique case that presented with hemodynamic abnormalities and severe bradycardia, necessitating the insertion of a temporary pacemaker, as well as metabolic disturbances, hematologic changes, and hepatic and renal dysfunction in an elderly individual owing to lithium intoxication. This case also demonstrates that these various serious side effects of lithium resolved with prompt recognition and discontinuation of lithium. Lithium should be used with extreme caution and frequent monitoring especially in the elderly.

Aged↗
PubMed1996

Pulmonary botryomycosis in a patient with AIDS.

We describe the clinical and pathologic findings of the first reported case of pulmonary botryomycosis in a patient with AIDS. Botryomycosis is an uncommon, chronic, suppurative disease that is often mistaken clinically and histologically for a fungal infection. The patient responded to systemic antibiotic therapy.

AIDS-Related Opportunistic Infections↗
PubMed1996

Small cell carcinoma of gallbladder: report of two cases.

Extrapulmonary small cell carcinoma has been reported from multiple sites, including the gallbladder. Small cell carcinoma of the gallbladder is a very rare tumor, found usually in elderly women and associated with cholelithiasis. It carries a grave prognosis, metastasizing early and causing death shortly after diagnosis. Treatment of metastatic disease with two different chemotherapeutic regimens has been shown to improve survival. To the best of our knowledge, this tumor has not been previously reported in a black individual, or in any subject less than 49 yr or more than 79 yr old. We report two cases: one is the first black and youngest reported case. The second is the oldest person reported with this rare malignancy. Radiological studies such as ultrasound and CT scan were useful in evaluating tumor spread and follow-up.

Adult↗
PubMed1995

Wandering spleen with torsion in a geriatric patient. Report of an unusual case with a brief review of the clinical picture and management.

Wandering spleen is a rare condition that is extremely uncommon in the elderly. A case of wandering spleen with torsion in a 73-year-old female is described in detail. Our patient's presentation is unusual because in 1972, during a total hysterectomy, she had no evidence of a wandering spleen. Preoperative technetium-99 radionuclide liver-spleen studies were utilized to minimize the potential for vascular difficulties. Splenectomy was the treatment of choice for this condition and was performed to avoid splenic infarction. A review of the literature and etiologic considerations are discussed.

Aged↗
PubMed1992

Recovery and loss of muscle force of rat plantaris after partial denervation.

The isometric contractile characteristics of rat plantaris muscles were assessed 1, 3, 6, 9, and 12 months after resection of the L4 radicular nerve. After 1 month of partial denervation, twitch and tetanus were significantly lower (26.1 and 22.1%, respectively) than those of sham-operated rats. Plantaris muscle weight was reduced (22.5%), but twitch-to-tetanus ratio (TW/TT), time-to-peak, and one-half relaxation time were not changed significantly. At 3 months, average twitch force was normal but average tetanic force was significantly lower (27.1%) than control value. Muscle weight was reduced (28.9%), but TW/TT was increased by 31%. After 6 months, twitch, tetanus, and all other variables were similar to those of control rats. Normal twitch at 3 months indicates that all muscle fibers have been reinnervated by sprouting from L5 motor axons; however, the new synaptic contacts may not support the tetanic response. At 9 months, muscle force was again reduced and remained at about the same level at the 12-month interval. These results are consistent with the recovery and loss of function seen in poliomyelitis and the postpolio syndrome.

Animals↗
PubMed1992

Long-term effects of partial denervation on sprouting and muscle fiber area in rat plantaris.

The long-term effects of partial denervation on the muscle fiber cross-sectional area, degree of axonal sprouting, and end-plate morphology were examined 1, 3, 6, 9, and 12 months postsurgery in rat plantaris muscle. After 1 month of partial denervation, mean cross-sectional areas of type I and type II myofibers were significantly lower than that of sham-operated controls; fiber atrophy and hypertrophy was observed. After 3 months, we found no statistical difference in the mean cross-sectional fiber area between the two experimental groups. After 6 months, the fiber areas were now significantly larger than controls, possibly the result of compensatory work hypertrophy, due to the overuse of remaining hyperexpanded motor units. Preterminal, intranodal, and intraterminal sprouting were found to significantly increase from 1 to 6 months following partial denervation. While sprouting was enhanced, the number of terminal branch points per end plate did not change. Following 9 months of partial denervation and overuse, the mean fiber areas significantly decreased as compared to controls. The former muscles were found to contain angulated fibers, group atrophy, and increased levels of axonal sprouting. The number of terminal branches per end plate was now significantly increased over control values, possibly a compensatory response to reduced synthesis of neurotrophic factor(s) and/or transmitter-related components. At 12 months, fiber areas, axonal sprouting, and the number of terminal branches per end plate have all decreased. Degenerating end plates, denervated myofibers, angulated fibers, and group atrophy were observed. It would appear that aging-like changes are occurring earlier in chronically stressed, partially denervated muscles.

Animals↗
PubMed1991

Nerve sprouting and endplate growth induced in normal muscle by contralateral partial denervation of rat plantaris.

The incidence of motor nerve and terminal sprouting was quantitatively analyzed in normal unoperated muscles, in homologous muscles contralateral to muscles which have been partially denervated, in partially denervated muscles, and in sham-operated muscles. Muscles were studied by light microscopy after staining motor endplates by a combined silver-cholinesterase stain. In addition, the incidence of endplates containing terminal sprouts, the number of terminal branch points per endplate, and endplate, and endplate size were also assessed in the various groups examined. We observed that following section of the L4 spinal nerve, the incidence of sprouting (preterminal and intranodal) in the contralateral muscle exhibited a 2-fold increase over sham-operated controls. We also found a correlation between nerve terminal sprouting, terminal branch point number and endplate size. All of these parameters were significantly increased in the contralateral muscles as compared to the sham-operated control muscles. These findings suggest that normal muscles undergo sprouting which can be enhanced by contralateral partial denervation. The possible underlying mechanism may be the transneuronal induction of sprouting.

Animals↗
PubMed1991

A rat model of the post-polio motor unit.

We examined the long-term effects of muscle usage on a rat model of the post-polio motor unit. Isometric tensions, type I and type II muscle fiber areas, the incidence of collateral sprouting, and motor endplate morphology were examined following 1, 3, 6, and 9 months of partial denervation in rat plantaris muscle. Full morphologic and functional stability of the expanded motor units occurred at 6 months post-partial denervation. Fiber hypertrophy was observed, possibly the result of compensatory work hypertrophy due to muscle overuse. Following 9 months of partial denervation and muscle overuse, the twitch and tetanic tensions and type I and type II muscle fiber areas were significantly reduced as compared to sham controls; angulated myofibers and group atrophy also were seen. The percent collateral sprouting, the number of terminal branches per endplate, and the endplate area were all increased, possibly a compensatory response to a decreased synthesis of neurotrophic factor(s) and/or transmitter-related components. These aging-like changes seem to occur earlier in chronically stressed, overenlarged, and overworked motor units.

Animals↗
PubMed1990

Tenotomy-induced motor endplate alterations in rat soleus muscle.

The effects of tenotomy on the ultrastructure of rat soleus muscle motor endplates were examined both qualitatively and quantitatively. Rat soleus muscle was studied 2 weeks following tenotomy and compared with normal littermates. The motor endplates from the tenotomized muscles were found to exhibit both degenerative and regenerative changes. Degeneration consisted of postjunctional fold breakdown, exposed junctional folds, myelin-like bodies within the sub-junctional sarcoplasm, and dense bodies within the Schwann cell cytoplasm. The regenerative changes consisted of several small nerve terminals occurring within the same primary synaptic cleft and several axons wrapped by the same Schwann cell. The results demonstrate that tenotomy induces denervation-like changes at endplates that lead to terminal sprouting within the neuromuscular junctional area and remodelling.

Animals↗
PubMed1989

Passive exercise and reinnervation of the rat denervated extensor digitorum longus muscle after nerve crush.

Denervated extensor digitorum longus muscles of Wistar rats were passively exercised for 4 days (2 h/day) after peroneal nerve crush 1 cm from the muscle. Isometric contractile properties and endplate ultrastructure were measured 11 days postcrush. No significant differences were observed in tension characteristics between the exercised and nonexercised muscles on day 11. However, the postsynaptic area of endplates for exercised muscles were closer in size to controls than those for the nonexercised ones. In addition, the endplates from the exercised muscles exhibited increased numbers of axonal sprouts and terminals than nonexercised muscles. These results demonstrate that denervated muscles exercised 4 days before reinnervation can preserve the structure of the endplate as well as enhance reinnervation and sprouting at these endplates after 11 days of denervation.

Animals↗
PubMed1986

The effect of electrical stimulation on reinnervation of rat muscle: contractile properties and endplate morphometry.

Denervated extensor digitorum longus muscles of Wistar rats were electrically stimulated in vivo for 4 days (2h per day) after peroneal nerve crush 1 cm from the muscle. Isometric contractile properties and endplate ultrastructure were measured on days 11 and 18. On day 11, the time to peak (116% of control) and 1/2-relaxation time (136% of control) for the twitch tensions of stimulated muscles measured in vivo were significantly less than those (127% and 157% of controls, respectively) of non-stimulated muscles. Peak twitch and tetanic tensions were not significantly different. The postsynaptic area of endplates for stimulated muscles were closer in size to controls than those for the non-stimulated ones. On day 18, no difference was found in the contractile responses between stimulated and non-stimulated groups. Similarly, the postsynaptic areas were the same for both groups. These results demonstrate that denervated muscle stimulated electrically for 4 days prior to reinnervation can preserve the structure of the endplate as well as accelerate recovery of normal function in reinnervated muscle fibers after 11 days of denervation.

Animals↗
PubMed1986

Structural alterations of the intramuscular nerves and junctional region in extraocular muscles of C57BL/Ks (db/db) diabetic mice.

The extraocular muscles of the C57BL/Ks (db/db) diabetic mutant mouse were examined by electron microscopy. The intramuscular myelinated nerves and the junctional apparatus of the singly and multiply innervated muscle fibers were found to exhibit various anomalies. Lamellated inclusion bodies were found in many of the Schwann cells of the myelinated nerve fibers; intra-axonal inclusion bodies resembling polyglucosan bodies were also observed. Junctional abnormalities consisted of various types of inclusion bodies within the junctional sarcoplasm and within sole-plate nuclei; in addition, hypertrophied endplates were observed and often penetrated by networks of axonal terminal branches. At times, pseudopod-like extensions of the junctional sarcoplasm encompassed and made protracted synaptic contacts with the incoming axons.

Animals↗