Biomedical subjects

R H Haas

Publications and source records attributed to R H Haas.

48 records · Page 3Linked to original sources

PubMed1988

The orthopedic management of Rett syndrome.

Musculoskeletal deformity sufficiently severe to require orthopedic surgery is a significant problem in Rett syndrome. Preliminary results from the study of 16 patients suggest deformity in nearly all patients. Eight patients in stage III and seven patients in stage IV showed clinical evidence of scoliosis. Radiographic studies confirmed a structural curve in nine of ten patients studied. Heel cord tightening was seen in nine of 16 patients. Hip instability was identified as an area of potential concern in the Rett patient.

Adolescent↗

PubMed1988

Recommendations regarding handling of the necropsy in Rett syndrome.

In order to maximize biochemical, neurochemical, molecular, and pathologic information from patients with Rett syndrome, a uniform procedure has been developed for the conduct of the postmortem examination. Tissue should be prepared for freezing, for electron microscopy studies, and for standard histologic examination. For the purposes of uniformity, three central repositories for necropsy materials have been established and are available at all times. In the event of the death of a patient with Rett syndrome, parents who consent to necropsy should request that materials be handled according to the protocol and transported under appropriate conditions to the central repository. The National Neurological Research Bank (Los Angeles), the Brain Tissue Bank (Belmont, Mass), and the Department of Neuropathology at Johns Hopkins Hospital (Baltimore) have agreed to serve as repositories for tissues. A committee of the International Rett Syndrome Association medical advisory panel will monitor this process in cooperation with the directors of the respective tissue banks.

Ammonia↗

PubMed1987

Interferon alfa-2b in the treatment of chronic granulocytic leukemia.

Studies of the effect of interferon on the growth of colonies of myeloid leukemic blasts, myeloma colony-forming cells and normal hemopoietic precursor cells have shown that interferon does not specifically inhibit the growth of the malignant cells in culture, i.e. the growth of the malignant and the normal precursor cells are inhibited equally. However, interferon markedly reduces the self-renewal capacity of acute myeloid leukemic blasts and myeloma cells. This observation suggested that interferon should be tested for its ability to prolong remissions rather than as a remission-inducing agent. We have tested the ability of interferon alfa-2b (Intron A; Schering-Plough) to prolong remissions induced by busulfan in patients with chronic granulocytic leukemia (CGL). The leukocyte doubling time (Td) and remission duration on no therapy was compared to the values observed during interferon alfa-2b maintenance therapy. Fourteen patients have been started on study and seven have received interferon alfa-2b for three months or more. All seven have shown slowing of the leukocyte Td and prolongation of the remission duration after interferon alfa-2b therapy. A larger study, with longer follow-up, will be required to determine whether interferon alfa-2b therapy will slow or prevent progression of CGL to the blast phase and prolong survival.

Adolescent↗

PubMed1986

Therapeutic effects of a ketogenic diet in Rett syndrome.

Seven girls (age 5 to 10 years) with Rett syndrome were investigated extensively. In 6 patients elevations of blood pyruvate were found. Blood lactate levels were marginally elevated. Two patients had variably elevated blood glucose levels. Metabolic studies were otherwise normal apart from minimally elevated blood ammonia levels in 3 of 5 patients tested, 2 of whom were on valproic acid. All 7 patients had anticonvulsant resistant seizures. EEG changes included generalized slowing and multifocal spike wave discharges, and pseudo-periodic burst-suppression patterns during sleep. Respiratory monitoring revealed apneic episodes only during the waking record. Six patients were below the 5th centile for weight despite normal caloric intake. Treatment with ketogenic diets, using medium chain triglyceride (MCT) oil when possible, has improved seizure control in the 5 patients who could tolerate the diet. Slight behavioral and motor improvement has occurred in these 5 patients and 6 of 7 patients on high fat diets have gained weight. With a possible defect in carbohydrate metabolism and a difficult seizure disorder, use of a ketogenic diet is logical and appears to produce clinical benefit in patients with Rett Syndrome.

Ammonia↗

PubMed1986

Interferon alfa-2b in the treatment of chronic granulocytic leukemia.

Studies of the effect of interferon on the growth of colonies of myeloid leukemic blast cells, myeloma colony-forming cells, and normal hemopoietic precursor cells have demonstrated that interferon shows no specificity in inhibiting the growth of these cells in culture (ie, growth of the malignant and normal precursor cells is equally inhibited). However, interferon markedly reduces the self-renewal capacity of acute myeloid leukemic blast cells and myeloma cells. This observation suggested that interferon's ability to prolong rather than induce remissions should be tested. We have studied the ability of interferon alfa-2b (Intron A) to prolong remissions induced by busulfan (Myleran) in patients with chronic granulocytic leukemia (CGL). The leukocyte doubling time and remission duration among patients receiving no therapy was compared with the values observed during interferon alfa-2b maintenance therapy. Nine patients have begun the study; five have completed 3 months of interferon alfa-2b therapy. In four (80%) of the five patients, there has been a significant slowing of the leukocyte doubling time and prolongation of the remission duration. A larger study, with longer follow-up, will be required to determine whether interferon alfa-2b therapy will slow progression of CGL to the blast phase and prolong survival.

Adult↗

PubMed1984

A microchamber for polarographic assay.

A glass micro-chamber which allows polarographic assay in a volume of 180 microliter is described. The conical shape of this chamber allows efficient mixing with a Teflon magnetic flea. This chamber facilitates the study of the small quantities of mitochondria obtained from human tissue biopsies or animal sources. The polarographic assay of mouse liver mitochondria is described.

Animals↗

PubMed1982

C-reactive protein in childhood dermatomyositis.

Serum levels of C-reactive protein (CRP) were determined in 9 patients with childhood dermatomyositis. Four children were seen during clinical relapse and all had serum CRP levels less than 1 mg/l. In addition direct immunofluorescent staining of muscle biopsies from 4 patients showed no evidence of CRP deposition in muscle tissue. Such patients appear to be able to produce CRP in response to acute infections, and it is suggested therefore that the pathological process in childhood dermatomyositis may not induce a significant CRP response.

Adolescent↗

PubMed1981

An X-linked disease of the nervous system with disordered copper metabolism and features differing from Menkes disease.

We studied 2 of 4 affected boys with a new disease associated with abnormalities of copper metabolism. The four cases occurred in two generations of a family. This syndrome was similar to Menkes disease in some respects: X-linked recessive inheritance, marked psychomotor retardation with seizures, low serum copper and ceruloplasmin levels, and a block in gut copper absorption. There were also striking differences from Menkes disease. Patients had normal birthweight at term, no hypothermia, and survived beyond the usual Menkes age group with static neurologic disease including hypotonia and choreoathetosis. In addition, general examination of both children was unremarkable apart from undescended testes and growth retardation. The hair, facies, and skin were normal and there was no radiologic evidence of bony changes. Detailed studies of copper absorption were performed.

Brain Diseases, Metabolic↗

PubMed1976

Adrenergic blockade in subarachnoid haemorrhage.

Over the last 15 years progressive interest has developed in the relationship between subarachnoid haemorrhage, sympathetic nervous system over-activity and the genesis of cerebral artery spasm. Following on from earlier work, vide infra, suggesting that adrenergic blockade might influence the course and prognosis of patients with subarachnoid haemorrhage, two double blind trials have recently been completed in Southampton. The first trial attempted to establish whether or not a single intracarotid injection of phenoxybenzamine improved the mortality and late morbidity of patients with subarachnoid haemorrhage. Results suggested that it did not. The second trial, comprising two groups of 50 patients each, attempted to assess the influence of prolonged treatment with propranolol on the course and prognosis of these subarachnoid haemorrhage patients. Early results suggest that, as with the alpha-blocker, the mortality and severe morbidity was not improved by beta-adrenergic blockade.

Adrenergic alpha-Antagonists↗

PubMedDate not supplied

Ketone bodies maintain normal cardiac function and myocardial high energy phosphates during insulin-induced hypoglycemia in vivo.

It has been suggested that myocardial utilization of ketone bodies might cause deterioration of cardiac function. Therefore, the influence of ketonemia (mean: 1.3 and 3.3 mM) in the presence of hypoglycemia (mean: 33 mg/dl) on cardiac function, substrate utilization and myocardial high energy phosphate levels was studied in 10 mongrel dogs. Hypoglycemia alone led to a significant increase of mean aortic pressure, total peripheral resistance and myocardial oxygen consumption, but other hemodynamic parameters and regional myocardial function were not changed. Additional infusion of 3-hydroxybutyrate did not affect hemodynamic variables significantly. During both metabolic interventions in vivo phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy showed stable levels of myocardial Pi, PCr, ATP, as well as PCr/Pi (3.2-3.4) and PCr/ATP (3.0-3.2) ratios. Biochemical measurements revealed that ketonemia led to significant alterations in arterial concentrations and arterio-coronary venous differences of selected citric acid cycle intermediates, thus confirming previous reports which suggested a blockade of the 2-oxoglutarate-dehydrogenase reaction induced by ketone body oxidation. However, despite this blockade, the energy supply to the heart was not impaired as shown by normal NMR spectroscopy and cardiac performance. It is speculated that the blockade might be due to an enhanced NADH/NAD ratio.

3-Hydroxybutyric Acid↗

PubMedDate not supplied

Electroencephalographic abnormalities in Rett syndrome.

Electroencephalograms were performed on 11 girls with Rett syndrome between the ages of 4 and 14 years. Electroencephalographic abnormalities included slowing and disorganization of background activity while awake, multifocal epileptiform discharges maximal over the central and temporal regions, and intermittent, high-amplitude discharges followed by relative attenuation of background activity during sleep. Electroencephalographic patterns were remarkably similar in all patients and may be of diagnostic assistance in suspected cases.

Adolescent↗

PubMedDate not supplied

Abnormalities of the brain in nonketotic hyperglycinemia: MR manifestations.

MR imaging in seven patients (4 days to 38 months old) with nonketotic hyperglycinemia showed age-related findings of progressive atrophy and delayed myelination. Parenchymal volume loss was found as early as 4 days after birth and increased in severity with increasing age to 27 months. Both supratentorial and infratentorial volume loss were present in the most severely affected patients. The corpus callosum was abnormally thin in all patients. The state of myelination of the CNS was assessed on T2-weighted images. Decreased or absent myelination within supratentorial white-matter tracts was detected in all four patients 10 months of age or older. Myelination of the brainstem and cerebellum progressed normally. No correlation was found between the degree of volume loss or abnormality of myelination demonstrated by MR and the concentration of glycine in the CSF or plasma. Abnormalities shown by MR correlate well with known pathologic findings in patients with nonketotic hyperglycinemia.

Amino Acid Metabolism, Inborn Errors↗