PubMed Health⌕ Search

Biomedical subjects

L Hoffman

Publications and source records attributed to L Hoffman.

At least 19 recordsLinked to original sources
PubMed1992

Multiple forms of the 20 S multicatalytic and the 26 S ubiquitin/ATP-dependent proteases from rabbit reticulocyte lysate.

We have used native gel electrophoresis followed by fluorogenic peptide overlay to identify multiple forms of rabbit reticulocyte multicatalytic protease (MCP) or 20 S protease, and two forms of rabbit 26 S ubiquitin/ATP-dependent protease. An abundant, fast-migrating 20 S complex (20 SF) possesses modest ability to hydrolyze the fluorogenic peptide succinyl-Leu-Leu-Val-Tyr-4-methyl-coumaryl-7-amide. In contrast, two minor, slower migrating species cleave the peptide at high rates. A unique 30-kDa polypeptide is associated with one of the active MCPs, and a 160-kDa subunit is associated with the other. Two electrophoretically distinct 26 S proteases can also be isolated from rabbit reticulocyte lysate. The faster migrating form, 26 SF, is more resistant to inactivation by ATP depletion. Despite the differential response to nucleotides and the distinctive electrophoretic mobilities of 26 SF and 26 SS, we have not identified any subunit differences between the two enzymes. In addition to active 26 S proteases, we have discovered and purified a proteolytically inactive particle that contains subunits characteristic of the 26 S protease (e.g. molecular masses between 30 and 110 kDa). Incubation of this protein complex with purified MCP and ATP results in the formation of the 26 S proteases.

Adenosine Triphosphate↗
PubMed1992

The effect of drug exposure on thyroid hormone levels of newborns.

This study examines the effect of women's alcohol abuse during pregnancy on the thyroid-stimulating hormone (TSH) and thyroxine (T4) levels of their babies at birth. Forty-seven babies were born to mothers identified as substance abusers. Maternal use of marijuana and/or cocaine did not result in newborns' TSH and T4 hormone levels being significantly different from non-substance-abusing controls' TSH and T4 levels. Alcohol use, however, was significantly linked to lower newborn TSH levels, lower than TSH levels of a control sample of newborns whose mothers used marijuana and/or cocaine, and lower than a control sample of newborns whose mothers abused no substances. This finding suggests further investigation of possible links between thyroid functioning and fetal alcohol syndrome (FAS).

Alcoholism↗
PubMed1992

Variations in digital nerve anatomy.

One hundred digital nerves from 10 cadaver hands were dissected, and branching patterns were analyzed. Contrary to the traditional belief that the digital nerve predictably trifurcates at the distal interphalangeal crease, much variation exists. Terminal branching occurred distal to the crease in 60% of the thumb digital nerves and in 78% of the digital nerves supplying the other four digits. The number of terminal branches also varied from two to seven in the thumb and from two to five in the other four digits. No significant differences were seen in branching patterns between digits or between radial and ulnar sides. These findings are clinically relevant to the surgeon who is contemplating digital nerve repair.

Cadaver↗
PubMed1992

On the clinical utility of the concept of depressive affect as signal affect.

The author reviews the scant literature relating to the concept of depressive affect as an affect parallel to anxiety. Then, through the presentation of detailed clinical psychoanalytic data, in particular the patient's associations to interpretation, he demonstrates the value to the conduct of a psychoanalysis of an awareness of the role of depressive affect as a signal affect that triggers defense.

Anxiety↗
PubMed1990

Constructing realities: an art of lenses.

In this essay I attempt to map the dimensions of my own move away from a cybernetic-biologic analogy for "family-systems" therapy. Central to this shift has been social construction theory augmented by two other lenses: a second-order view, and a sensitivity to gender. These conceptual tools have helped me to distance myself from my previous therapeutic stance and to envision a very different model, one that is less strategic and instrumental, and more collaborative and unconcealed.

Cognition↗
PubMed1989

Low plasma beta-endorphin in post-traumatic stress disorder.

We compared serum cortisol, ACTH and plasma beta-endorphin in 21 Post-Traumatic Stress Disorder patients and 20 controls. Although we found no important disturbance in diurnal rhythms, the PTSD patients had significantly higher A.M. serum cortisols compared with controls. Both A.M. and P.M. plasma beta-endorphins in PTSD patients were significantly lower compared with controls. These data suggest that plasma beta-endorphin may be a marker for PTSD and that chronic endogenous opioid depletion may play a role in the pathogenesis and perpetuation of this disorder.

Adrenocorticotropic Hormone↗
PubMed1989

Chronic high velocity projectile injury to the foot.

Acute projectile injuries to the foot can present a challenge for the podiatric physician, especially in terms of their chronic effects. The case of a shrapnel wound to the right foot and ankle that resulted in recurrent episodes of soft tissue infection and disability is presented. Treatment consisted of excision of the shrapnel fragment, debridement, and primary closure of the sinus tract created by the projectile. The authors discuss the acute and chronic effects of projectile injuries, factors responsible for determining the severity of these wounds, and various methods of treatment.

Acute Disease↗
PubMed1989

The psychoanalytic process and the development of insight in child analysis: a case study.

This paper describes a segment of the analysis of an aggressive latency-age child. The data demonstrate the relationship between the establishment of a psychoanalytic process (the analysis of transference, defense, and resistance), the development and nature of insight in the child, and the resulting therapeutic change. Examination of the process shows that the therapeutic gains were a result of insights acquired by the child, particularly his awareness of painful affects that had been warded off. This case is compared with Bornstein's treatment of a phobic child who manifested severely "out-of-control" behavior.

Acting Out↗
PubMed1988

The neuropsychiatry of post-traumatic stress disorder.

The publication of DSM-III introduced the diagnosis Post-Traumatic Stress Disorder (PTSD), thus providing, for the first time, a framework for studying the consequences of extremely stressful events. Previously, traumatic neuroses had attracted a wide variety of labels - as wide as the experiences that produced them. Competing explanations in psychological and biological terms have characterised the approach to these disorders, and social and legal issues have added to the confusion. In recent years, psychosocial issues have tended to dominate the literature in relation to PTSD. While acknowledging the importance of such phenomenological and psychosocial approaches, this paper seeks to redress the balance by focusing on a biological perspective.

Dominance, Cerebral↗
PubMed1986

Elevated serum creatinine levels in three patients treated with phenacemide.

Three adolescent patients with severe seizure disorders were treated with phenacemide. All three patients showed elevated serum creatinine and normal blood urea nitrogen values while on phenacemide. Simultaneous urea and creatinine clearance studies performed on each patient demonstrated normal urea clearances and decreased creatinine clearances. Inulin clearance performed in one patient was normal. The medication was discontinued in two of the patients because of co-existing neutropenia. Serum creatinine values returned to normal after phenacemide treatment was terminated. The elevation in serum creatinine values with phenacemide appears to be dose related, reversible, and unrelated to impairment of glomerular filtration.

Adolescent↗
PubMed1984

Boilermakers' bronchitis. Respiratory tract irritation associated with vanadium pentoxide exposure during oil-to-coal conversion of a power plant.

Severe respiratory tract irritation occurred in at least 74 of 100 boilermakers who were exposed to high levels of vanadium pentoxide fume during oil-to-coal conversion of a utility company power plant in a rural area of western Massachusetts. Many were welders working in confined areas with inadequate ventilation. Most frequent symptoms were productive cough, sore throat, dyspnea on exertion, and chest pain or discomfort. The illness was severe enough to cause 70 workers to consult physicians and most of them to lose time from work (median, five days). Wheezing (in 39%) was the most frequent finding on physical examination. Mild hypoxemia was noted in several workers; most (72%) had normal chest x-ray films. Expiratory flow rate over the middle 50% of the forced vital capacity was the pulmonary function test most remarkably affected (median, 57% of predicted for 24 workers tested). The Occupational Safety and Health Administration documented levels of vanadium pentoxide fume at or above the permissible exposure limit in all eight air samples taken from inside the boiler; it cited the company for inadequate mechanical ventilation and an inadequate respiratory protection program for workers. The report of this outbreak may help prevent future problems by drawing attention of physicians, workers, and managers to the potential pulmonary hazards in power plant conversion.

Adult↗
PubMed1983

A comparison between islet transplantation and parenteral insulin in the control of diabetes and prevention of renal complications in mice.

The control of diabetes and the prevention of renal complications were studied in mice that received different treatment regimes for six months. Transplantation of syngeneic cultured fetal pancreas completely reversed streptozotocin-induced diabetes (mean FBG 5.1 +/- 0.4 mmole/liter six months after transplantation, versus 5.8 +/- 0.2 mmole/liter in normal mice). The mean fasting blood glucose (FBG) level of insulin-treated mice was lower than the mean FBG level of untreated diabetic mice (9.0 +/- 1.2 mmole/liter versus 11.5 +/- 1.3 mmole/liter, P less than 0.05) but exceeded the FBG level of transplanted mice (P less than 0.001) or normal controls (P less than 0.001). There were no significant differences between the mean level of glycosylated hemoglobin (HbA1c) of normal (4.8 +/- 0.3%), transplanted (4.5 +/- 0.3%), or insulin-treated mice (5.3 +/- 0.4%), but the HbA1c level in the untreated diabetic group was increased (7.0 +/- 0.5%; P less than 0.001). Six months after transplantation, the thickness of the glomerular capillary basement membrane (GCBM) was not different in the transplanted group and normal controls (156.4 +/- 5.7 nm versus 157.3 +/- 12.6 nm); the GCBM was thicker in the insulin-treated mice than in the transplanted mice (179.8 +/- 4.2 nm versus 156.4 +/- 5.7 nm; P less than 0.02), but thinner than in untreated diabetic mice (179.8 +/- 4.2 nm versus 202.2 +/- 4.4 nm; P less than 0.001). It is concluded that islet transplantation, in contrast to good control as judged by normalization of HbA1c levels achieved with parenteral insulin, prevents GCBM thickening in experimental diabetes.

Animals↗
PubMed1982

Insulin secretion by fetal human pancreas in organ culture.

Whole fetal human pancreases of 12-22 weeks gestation, showed histological growth and differentiation in vitro over 3 weeks. At glucose concentrations of 1-4 g/l, there was no difference in insulin secretion into culture medium over 1 h. There was no stimulation of insulin release by D-glyceraldehyde, thus defective glucose-stimulated insulin release was probably not due to impairment of an early step in glycolysis. In the presence of 0.5 mmol/l dibutyryl cyclic AMP, insulin secretion was enhanced (0.188 +/- 0.030 versus 0.100 +/- 0.012 mU x mg tissue-1 x h-1, p less than 0.001) independently of glucose concentrations. It thus appears that impairment of glucose-stimulated insulin release was unlikely to be due to insufficient intracellular cyclic AMP. Insulin release increased in response to tolbutamide and theophylline. Insulin secretion was stimulated in the presence of a fivefold increase in amino acid concentration (0.118 +/- 0.018 versus 0.031 +/- 0.008 mU x mg tissue-1 x h-1, p less than 0.001). There was a fourfold increase in basal insulin secretion from islets previously grown in high concentration of amino acids compared with standard culture medium, (0.284 +/- 0.052 versus 0.067 +/- 0.011 mU x mg tissue-1 x h-1, p less than 0.001), emphasizing the important role of amino acids as substrates for B cell metabolism and development.

Amino Acids↗