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Biomedical subjects

J Towfighi

Publications and source records attributed to J Towfighi.

At least 19 recordsLinked to original sources
PubMed1992

Early onset autosomal dominant progressive muscular dystrophy presenting in childhood as a Becker phenotype--the importance of dystrophin and molecular genetic analysis.

We present two cases of autosomal dominant limb girdle muscular dystrophy in a father and son. Both presented in childhood with a classical Becker muscular dystrophy phenotype. The father had initially been informed that he would not have affected children. After the diagnosis of muscular dystrophy in the son, immunoblot analysis was performed on muscle and revealed normal dystrophin. The polymerase chain reaction did not show any deletions in the dystrophin gene, and the father's dystrophin gene was not passed to his son. These cases demonstrate that autosomal dominant muscular dystrophy may present in childhood, and that dystrophin and molecular genetic analyses should be performed when considering the diagnosis of childhood muscular dystrophy, even in the presence of a classical phenotype.

Child↗
PubMed1992

Effect of insulin-induced and fasting hypoglycemia on perinatal hypoxic-ischemic brain damage.

Experiments in adult animals have indicated that hyperglycemia accentuates whereas hypoglycemia ameliorates hypoxic-ischemic brain damage. To determine whether hypoglycemia is protective or deleterious to the perinatal brain subjected to hypoxia-ischemia, 7-d postnatal rats were rendered hypoglycemic either by receiving an s.c. injection of insulin or fasting for 12 h. All rat pups underwent unilateral common carotid artery ligation followed by exposure to 8% oxygen-balance nitrogen at 37 degrees C for 2 h. Control animals (no insulin or fasting) received s.c. injections of normal saline. Mean blood glucose concentrations were 5.4 +/- 0.1, 4.3 +/- 0.2, and 3.4 +/- 0.1 mmol/L for control, insulin, and fasted animals, respectively. Blood beta-hydroxybutyrate concentrations were identical (0.5 +/- 0.1 mmol/L) for control and insulin-treated animals, but more than doubled in concentration in the fasted animals (p less than 0.001). Mortality rates during hypoxia-ischemia were higher in the insulin-treated animals (30%) than in either the fasted (4%) or control (0%) animals (p less than 0.05). Fasted animals showed a significant reduction in hypoxic-ischemic brain damage as compared with either the insulin-treated or control animals. Insulin-treated animals were not significantly different from controls. The findings indicate that 1) insulin induced hypoglycemia does not provide a protective effect on perinatal hypoxic-ischemic brain damage, as in adults; and 2) fasting adequate to produce hypoglycemia and ketonemia improved neuropathologic outcome.

Animals↗
PubMed1991

Spinal cord abnormalities in caudal regression syndrome.

Caudal regression syndrome includes malformations ranging from mild forms of sacral agenesis to severe limb anomalies referred to as sirenomelia. The latter, in addition to sacral anomalies, shows malformed single lower limb and agenesis of rectum and genitourinary tracts. We report the neuropathologic examination in four infants, three with sirenomelia and one with lumbosacral agenesis. Brain and spinal cord were normal except for the structures in the caudal region of the spinal cord that were abnormal in all four cases. The first sirenomelic case with a mild sacral hypoplasia had only minor fusion of a few sacral roots and a slightly low-positioned conus medullaris. The second sirenomelic case with an intermediate degree of sacral hypoplasia had fusion of some of the sacral roots and ganglia, spinal ganglion cell heterotopias, filar lipoma and absence of the last sacral roots and ganglia. The third sirenomelic case with a severe degree of sacral hypoplasia showed additional tethering of the spinal cord. Case four with the agenesis of the lumbosacral spine had a total lack of the lumbosacral spinal cord, and dysplasia of the T11 and T12 cord segments. These findings suggest that the extent of anomalies of the caudal spinal cord structures in the caudal regression syndrome are roughly proportional to the anomalies of the vertebral column, and that they may constitute some of the main components of this syndrome.

Abnormalities, Multiple↗
PubMed1991

Cerebro-ocular dysplasia--muscular dystrophy (Walker Warburg) syndrome. Findings in 20-week-old fetus.

A 20-week fetus affected with cerebro-ocular dysplasia and muscular dystrophy (Walker-Warburg Syndrome) is reported. The central nervous system (CNS) findings were typical of those previously described in this disorder, and were characterized by lissencephaly, hydrocephalus, and cerebral and cerebellar cortical dysplasia with glial and neuronal displacement into the leptomeninges. In addition, severe hypoplasia of pyramidal tracts were noted in the brain stem and spinal cord, as well as malformation of the inferior olivary and dentate nuclei. Skeletal muscle and eyes appeared normal on light microscopy. The genetic defect in this disorder is expressed in the CNS early during the first trimester and causes a marked disorder of cellular migration. Overt changes in muscle occur during a later period. The changes in the CNS are similar to, but more severe than, those found in Fukuyama congenital muscular dystrophy, and both may represent a failure of constraint of neuronal migration. Whether the syndromes characterized by cerebro-ocular dysplasia and muscular dystrophy are genetically heterogeneous or allelic variations is unknown. Molecular genetic analysis should elucidate this question.

Brain↗
PubMed1991

Neuropathology of remote hypoxic-ischemic damage in the immature rat.

This study was undertaken to determine: (a) the duration of hypoxia required to produce brain damage in immature rats with unilateral carotid artery ligation (Levine technique); (b) the regions of immature brain most vulnerable to hypoxia-ischemia (HI); and (c) the neuropathology of the remote HI insult. To this end, 7-day postnatal rats, subjected to unilateral carotid artery ligation combined with hypoxia of varying durations (45, 60, 75 or 90 min), were killed at 30 days of postnatal age and their brains examined by light microscopy. The results indicated that a longer duration of HI was more likely to produce brain lesions and that the extent and severity of the lesions closely correlated with the length of HI. Shorter intervals of HI primarily damaged the cerebral cortex and hippocampus, while longer periods resulted in more extensive damage and were often associated with cavitary lesions of the cerebral hemisphere. Comparison of HI brain damage produced by the Levine technique in immature and adult rats suggested that in immature rats: (a) the cavitary lesions were common; (b) the non-cavitary cortical lesions had a tendency to show a vertical band-like distribution - a pattern never seen in adults; and (c) the lesions often showed mineralization. The similarities between these experimentally produced HI cerebral lesions and those observed in the developing human brain, such as ulegyria and porencephaly, are discussed.

Amygdala↗
PubMed1991

Brain energy consumption in ethanol-treated, Long-Evans rats.

The cerebral metabolic rate of glucose utilization (CMRGlc) was measured in rats fed liquid diets containing ethanol for 8 wk, after removal of ethanol from the diet and after acute ethanol intoxication. Control rats were pair fed the liquid diets containing isoenergetic amounts of dextrin-maltose. Quantitative autogradiography using [6-14C]glucose measured CMRGlc at the level of individual structures. Digital image techniques created stereograms of brain energy consumption from the autoradiographs. These techniques provided information about CMRGlc throughout the brain. Rats given the ethanol liquid diet drank constantly throughout the day and night. Neuropathological examination of brain revealed no abnormalities from ethanol consumption. Acute ethanol administration to control rats produced a decrease in CMRGlc throughout the brain that was most prominent in structures concerning auditory, visual, memory and motor functions. Chronic ethanol consumption did not reduce CMRGlc to the same degree as acute ethanol intoxication; in fact, it affected only a few structures. The removal of ethanol from chronic ethanol-treated rats for a period of 18 h caused CMRGlc to rise above control values throughout the brain. However, there were no seizures or other evidence of brain dysfunction.

Alcohol Drinking↗
PubMed1991

Extramedullary hematopoiesis in cerebellar hemangioblastoma.

Extramedullary hematopoiesis and paraneoplastic erythrocytosis are uncommon in cerebellar hemangioblastoma, and their concomitant occurrence has not been reported. In a study of 26 cases of hemangioblastoma, we found extramedullary hematopoiesis in 4 tumors; one was associated with erythrocytosis. The significance of this association and the possible histogenetic origin of extramedullary hematopoiesis in cerebellar hemangioblastoma are discussed.

Adolescent↗
PubMed1991

Sternohyoid muscle biopsy. A diagnostic technique in respiratory failure of neuromuscular origin.

Patients with neuromuscular disease may develop respiratory failure requiring mechanical ventilation. We describe a sternohyoid muscle biopsy technique as a diagnostic aid in such patients undergoing tracheostomy for prolonged ventilatory support. The biopsy procedure is quick and without added discomfort or morbidity for the patient. Our preliminary observations in three patients suggest that the sternohyoid muscle biopsy may be a useful diagnostic tool in this selected group of patients.

Adolescent↗
PubMed1990

Mannitol therapy in perinatal hypoxic-ischemic brain damage in rats.

To study the efficacy of mannitol in reducing cerebral edema and improving the ultimate neuropathologic outcome in perinatal cerebral hypoxia-ischemia, 67 7-day postnatal rats were subjected to unilateral common carotid artery ligation followed by exposure to 8% oxygen at 37 degrees C for 3 hours. Twenty-seven rat pups received a subcutaneous injection of 0.1 ml mannitol in a dosage of 4 mg/kg body wt immediately following cerebral hypoxia-ischemia and every 12 hours thereafter for a total of four doses. Control animals received either no therapy (n = 16) or an equivalent volume of normal saline (n = 24). Mannitol injections in six rat pups not subjected to hypoxia-ischemia produced no mortality but significantly increased serum osmolality from 287 to 361 mos/l (p less than 0.01). Preliminary studies indicated that substantial mortality occurred when greater doses of mannitol were administered to rats. After 48 hours of recovery from hypoxia-ischemia, the animals were killed and their brains were examined for either tissue water content (33 rat pups) or the presence of neuropathologic alterations (34 rat pups). Mannitol significantly reduced (p less than 0.001) brain water content, as a reflection of cerebral edema, in both the ipsilateral (88.5% compared with 90.6% in controls) and the contralateral (85.0% compared with 87.2% in controls) cerebral hemispheres. Mannitol therapy did not ameliorate the incidence, distribution, or severity of tissue injury in the cerebral cortex, subcortical white matter, hippocampus, striatum, or thalamus of the ipsilateral cerebral hemisphere compared with the controls. Thus, while mannitol substantially reduces the extent of cerebral edema following hypoxia-ischemia, no beneficial affect on ultimate brain damage occurs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Physiologic and neuropathologic aspects of hypothermic circulatory arrest in newborn dogs.

A model of hypothermic circulatory arrest has been developed in the newborn dog. Ten puppies were anesthetized with halothane, paralyzed, and artificially ventilated with 70% nitrous oxide 30% oxygen to arterial oxygen pressure greater than 8.0 kPa (60 mm Hg), arterial carbon dioxide pressure of 4.4-5.6 kPa (33-42 mm Hg), and arterial pH of 7.35-7.42. Animals were surface cooled to 20 degrees C, after which cardiac arrest was produced with i.v. KCl. Dogs remained asystolic without ventilation for 1.0 (n = 4), 1.5 (n = 3), or 2.0 (n = 3) h. Resuscitation was accomplished with closed-chest compression, mechanical ventilation, i.v. epinephrine and NaHCO3, and rewarming to 37 degrees C. Postarrest recovery was maintained for 3-4 h; thereafter, the puppies underwent perfusion-fixation of their brains for pathologic analysis. Plasma glucose (control = 8.3 mmol/L) increased slightly during hypothermic cardiac arrest (+36%) but was markedly elevated at 15 min postarrest (20 mmol/L). Blood lactate (control = 1.1 mmol/L) increased almost 200% during hypothermic circulatory arrest, with a further rise to 9.0 mmol/L at 15 min postarrest. Thereafter, lactate decreased in the 1-h arrested dogs but increased progressively in the other groups. Mean arterial blood pressure returned to baseline (73 mm Hg) by 15 min postarrest, remained stable in the 1-h dogs, but fell at 3 h to 62 and 34 mm Hg in the 1.5- and 2.0-h groups, respectively. No neuropathologic alterations were seen in puppies arrested for 1 h, whereas all puppies arrested for 1.5 or 2 h had varying degrees of cerebral cortical and hippocampal damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

Möbius syndrome. Neuropathologic observations.

Neuropathologic findings in an infant with congenital right facial and bilateral lateral rectus palsy (Möbius syndrome) are presented. Multiple microscopic foci of necrosis were found in the lower pontine tegmentum, involving the region of the intramedullary course of 6th and 7th cranial nerves. The significance of pathologic findings in this infant and 14 additional published cases of Möbius syndrome is discussed.

Abducens Nerve↗
PubMed1978

Neurologic complications of acute myelomonoblastic leukemia of four years' duration.

An adult with acute nonlymphoblastic leukemia involving the central nervous system is presented. Unusual features included: (1) Focal signs and radiographic evidence of sagittal sinus occlusion early in the course of disease; (2) progressive meningeal, cranial nerve, and spinal nerve involvement despite a 4-year bone marrow remission; (3) intracerebral tumor formation, and (4) retrobulbar optic neuritis associated with microscopic findings of herpeslike viral particles. The incidence of clinically overt neurologic disease in adults with acute nonlymphoblastic leukemia seems to have increased in tandem with improved chemotherapy. The prophylactic treatment of the central nervous system during prolonged remission of adult acute nonlymphoblastic leukemia may prove of benefit to these patients.

Adult↗
PubMed1977

Spongy degeneration of the central nervous system (van Bogaert-Bertrand type?) in a newborn infant. A light and electron microscopic study.

Autopsy findings on a 5 day old infant with hypotonia from birth showed extensive spongy changes of the myelinating tracts within the cerebrum, cerebellum and brain stem. The spongy changes, similar to Van Bogaert-Bertrand disease, resulted from intramyelinic edema. However, unlike the typical forms of this disease, swollen astrocytes with abnormal mitochondria were not found. The relationship of this case to typical forms of Van Bogaert-Bertrand disease is discussed. This case may represent a very early form of Van Bogaert-Bertrand disease or a new pathological entity.

Astrocytes↗
PubMed1977

The distribution of peroxidases in the sciatic nerves of normal and hexachlorophene intoxicated developing rats.

Horseradish peroxidase (mol. wt. 40 000) or microperoxidase (mol. wt. 1900) were injected over the sciatic nerve of normal or hexachlorophene (HCP) intoxicated developing rats (3,7,14 and 21 days). Light and electron microscopic studies of nerves after histochemical staining for peroxidase revealed: a) the perineurial barrier to the two peroxidases was established in 21 day normal and HCP intoxicated rats; b) in animals 3-14 days, the perineurial barrier to both peroxidases was not formed and peroxidase staining was observed in the periaxonal space and in the space between paranodal loops of myelin; c) intramyelinic vacuoles, induced by HCP in animals 7-14 days did not show peroxidase staining. HCP-induced intramyelinic vacuolation is due to the separation of the myelin lamellae at the intraperiod line; although these vacuoles are potential extensions of the extracellular space, they are not stained with the extracellular markers horseradish or microperoxidase.

Age Factors↗
PubMed1976

Glue sniffer's neuropathy.

Progressive sensorimotor neuropathy developed in two patients exposed to prolonged (chronic) inhalation of n-hexane (glue sniffing). Sural nerve biopsies showed loss of axons; remaining axons were either normal or showed accumulation of filaments of 90 to 100 A thick, widened nodes of Ranvier, and focal enlargements. The muscle biopsy revealed neurogenic atrophy. Intramuscular nerve twigs and end-plates, studied in one patient, showed loss of axons and nerve terminals. Unmyelinated axons also showed accululation of 60 to 100 A thick filaments. The similarities between the pathologic findings in the peripheral nerve of these patients and those with acrylamide neuropathy suggest that the n-hexane inhalation produces a dying back neuropathy.

Adult↗
PubMed1976

Sarcoidosis of the spinal cord. Case report.

A case of intramedullary sarcoidosis simulating a tumor of the cervical spinal cord is presented. Autopsy showed that the disease was limited to the cervical cord and hilar lymph nodes. The literature is reviewed and six cases of histologically documented spinal cord sarcoidosis are discussed.

Adult↗