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Biomedical subjects

U Dietrich

Publications and source records attributed to U Dietrich.

At least 73 records · Page 4Linked to original sources
PubMed1993

HIV-1 strains from India are highly divergent from prototypic African and US/European strains, but are linked to a South African isolate.

OBJECTIVE: To gain molecular insights into different HIV-1 strains present in two different states of India, nucleotide sequences derived from the env region of four HIV-1 strains were analysed. DESIGN: HIV-1 was isolated from high-risk patients from the states of Maharashtra (city of Bombay) and Goa. The molecular analysis of the env region encompassed all variable domains of the external glycoprotein, gp120. METHODS: Genomic DNA from cultured cells infected with each of the four Indian HIV-1 strains independently was amplified by polymerase chain reaction (PCR). PCR fragments were cloned and sequenced and a phylogenetic tree constructed. RESULTS: All four Indian HIV-1 sequences were closely related to each other. The closest related sequence to them was from a South African isolate, HIV-1NOF, with a homology of 85-87%. In the phylogenetic tree, the Indian and the South African HIV-1 sequences cluster together and constitute a subtype different from the North American/European, Central African, Uganda/Rwanda and Northern Thailand subtypes. Interestingly, the viruses of this subtype are characterized by an additional potential N-glycosylation site C-terminal to the CD4-binding domain. CONCLUSION: The low variation between the HIV-1 sequences from randomly chosen individuals from high-risk cohorts in two Indian states suggests a rapid and recent spread of HIV and, possibly, introduction of the virus by the same route, most probably heterosexual transmission. The rapid spread of HIV-1 variants in India, which form a subgroup of their own together with a South African strain, necessitate consideration of these strains in vaccine development.

Africa↗
PubMed1993

[Localization of frontobasal traumatic cerebrospinal fluid fistulas. Comparison of radiologic and surgical findings].

Computed tomographic and surgical findings were compared in 30 patients with traumatic frontobasal cerebrospinal fluid fistula. Radiological signs were extension of fractures of the rhinobasis, localized opacification of paranasal sinuses, and localized intracranial air collections. Exact localization of dural tears was only possible in about half of all patients (16 of 30). In conclusion there must be surgical inspection of all fractures of the skull base, and only isolated injuries could be treated by selective surgery.

Adult↗
PubMed1992

Subarachnoid hemorrhage of unknown origin. Longterm prognosis.

Patients suffering subarachnoid hemorrhage in whom angiography does not initially show vascular malformation and CT scan rules out an intracranial tumor, have, reportedly, a good prognosis with a rate of recurrent hemorrhage of about 2-10% within a follow-up time of up to 15 years. Most authors denied indication for control angiography. In order to study the benefit of control angiography performed after 4-6 weeks, four-hundred eighty-three patients with SAH but without ICH were reveiwed, and the longterm clinical course of 98 patients with SAH of unknown origin treated in our department between 1976 and 1988 was investigated. Among 183 patients who underwent control angiography, a second angiography showed an aneurysm in 143. The third angiography was positive in a further 18 patients. Recurrent SAH occurred early only in patients who had undergone only one angiography. One patient died from intracerebral hemorrhage of unknown origin two years following SAH. These data support the need for control angiography in cases of SAH.

Adolescent↗
PubMed1992

Analysis of the envelope region of the highly divergent HIV-2ALT isolate extends the known range of variability within the primate immunodeficiency viruses.

HIV-2ALT is a highly divergent HIV-2-related isolate that is genetically equidistant to the prototypic HIV-2 strains, defined by HIV-2ROD, and to the simian immunodeficiency viruses SIVmac and SIVsm. We have now cloned and sequenced the envelope region of HIV-2ALT, thus completing the analysis of the whole viral genome. The sequences of env and nef and of the second exons of tat and rev were compared with those of the other viruses of the HIV-2/SIVsm/SIVmac group. Despite of the high degree of variation of HIV-2ALT, functional domains of the genes are conserved. Although in env, the overall pattern of constant and variable domains is maintained, many single amino acid exchanges exist at positions previously thought to be constant in HIV-2 strains. In addition, when compared with a broader spectrum of immunodeficiency viruses, which includes SIVMND from mandrill and SIVAGM from African green monkey, HIV-2ALT Env has a high percentage of amino acid exchanges, which are unique to this strain. This underlines the separate branch of HIV-2ALT within the phylogenetic tree and makes obvious the inclusion of such divergent strains in preventive and therapeutic programs.

Amino Acid Sequence↗
PubMed1992

HIV-1 and HIV-2 infections in a high-risk population in Bombay, India: evidence for the spread of HIV-2 and presence of a divergent HIV-1 subtype.

A high-risk population (patients of a sexually transmitted disease clinic and the GT hospital in Bombay) was tested for antibodies against HIV-1 and HIV-2. Among 405 serum samples, 226 had previously been classified HIV-positive in India using different locally available enzyme-linked immunosorbent assay (ELISA) tests. The serology of 179 samples was unknown. All 405 samples were tested at the Georg-Speyer-Haus (GSH) with the Pasteur HIV-1/2-Combi-ELISA. Positive samples were further analyzed with HIV-1 and HIV-2 Western blot kits from Dupont and Pasteur, respectively. A very high seroprevalence of HIV was found in this population. Among the 179 unscreened samples, 69 (38.5%) were positive in the ELISAs as well as the Western blots for HIV-1 or HIV-2. Among the prescreened samples, only 174 (77%) were confirmed HIV-positive. Altogether, 243 of 405 sera were HIV-positive. Of these, 184 (76%) were reactive with HIV-1, 10 (4%) were reactive with HIV-2, and 49 (20%) had dual reactivity to HIV-1 and HIV-2. Previous data from the Indian Council of Medical Research had already suggested a possible high prevalence of HIV-1 in India. Our results confirm this view. The finding of a substantial spread of HIV-2 infection was, however, totally unexpected in India, but confirms our previous study which had already demonstrated the existence of HIV-2 in this country. Asia can thus no longer be considered free of HIV-2, and testing for HIV-2 appears mandatory, at least in India.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1992

[Diagnostic aspects of isolated sphenoid sinusitis].

The clinical occurrence of isolated sphenoid sinusitis is rare. Due to a long history and few initial symptoms, diagnosis of this potentially fatal infections can be difficult. Radiological aspects in 10 patients are presented (e.g. type and design of examination and whether inflammatory or destructive changes could be shown), as well as clinical aspects (cranial nerve palsy, concurrent inflammation, duration of disease and therapy). CT proved to be superior in diagnosing the extent of any bony changes, while MRI was more useful in detecting inflammation.

Adolescent↗
PubMed1992

[The question of oral sedation using midazolam in outpatient dental surgery].

The aim of the present study was to evaluate the effect of one tablet of midazolam (Dormicum 7.5 mg) used as a premedicant for minor oral surgery and to assess the potential risk of hypoventilation. In all of the patients no significant drop in arterial oxygen saturation could be observed, but on the other hand, no real anxiolytic or amnestic effects either. With the little therapeutic use observed with the given premedication, a more widespread application of the substance in this dosage cannot be recommended, particularly when taking into account the possibility of complications and the loss of the patients's fitness to drive for the next twelve hours.

Anesthesia, Dental↗
PubMed1991

Biochemical and genetical analysis of AZT-resistant HIV-mutants.

Sequential virus isolates from an HIV-1-infected woman treated orally with 3'-azido-3'-deoxythymidine (AZT) for over two years showed a 10-fold reduced sensitivity for AZT after 8 months and a 100-fold resistance after 24-32 months of drug therapy. These AZT-resistant mutants were totally sensitive in vitro to other reverse transcriptase (RT)-inhibitors like the AZT-analogue 3'-fluoro-3'-deoxythymidine (FdT) or the chemically less related nucleoside analogue 2',3'-dideoxycytosine (ddC). Even the benzodiazepin derivative 4,5,6,7-tetrahydro-5-methyl-6-(3-methyl-2-butenyl)-imidazo [4,5,1-jk][1,4]-benzodiazepin-2(1H)-thione (TIBO), a new drug specific for HIV-1 RT, was inhibitory for these virus strains. Moreover, compounds with different modes of action, e.g. polysulfated polyxylan, exhibited full antiviral activity as well. Thus, AZT resistance seems to be highly specific and should allow to develop further drugs to be used when AZT resistance has emerged. 5.9 kb fragments of the 5'-genomic halves of these sequential HIV-isolates were amplified by PCR and cloned. DNA sequence analysis revealed that the RT gene of the two highly AZT-resistant isolates carried two of the mutations described by Larder et al. [Science 246, (1989)], the Lys 70----Arg and the Thr 215----Tyr transitions. The isolate obtained after 32 months of AZT-therapy in addition contained a third mutation at position 67 (Asp----Asn); in contrast to Larder's report, no mutation was found at position 219. Thus, although these virus isolates showed at least a 100-fold reduced susceptibility for AZT in vitro, the four mutations postulated to be relevant for highly resistant strains were only partially confirmed.

Amino Acid Sequence↗
PubMed1990

Clinical experience with a pressure-adjustable valve SOPHY in the management of hydrocephalus.

Seventy-four patients with hydrocephalus due to a variety of causes were treated with a cerebrospinal fluid (CSF) shunt, incorporating a recently developed pressure-adjustable valve SOPHY (PAVS). The PAVS may be changed percutaneously with the help of an externally applied magnet in order to select a high-, medium- or low-valve opening pressure, whenever the need for a change in pressure characteristics seems necessary to the neurosurgeon. The percutaneous pressure adjustment obviated up- or downgrading of a medium pressure position by surgical means in half of our patients during the follow-up time (up to 39 months; mean follow-up 16.7 months). In 66 patients (89%) decreased ventricle volume and improvement of the clinical sign of increased intracranial pressure were established. In 11 patients a valve or a catheter infection occurred; in 6 of these patients the valve had to be removed. Half of this group consisted of patients under 2 years of age. Significant technical complications related to the PAVS did not occur in our series but until a somewhat smaller PAVS is available, we cannot recommend its use in neonates or in small infants. In all other patients the PAVS is a very valuable instrument in the surgical management of hydrocephalus because it makes shunt revisions for inadequate valve pressure obsolete in individual patients.

Adolescent↗
PubMed1990

[Computed tomographic assessment of orbital fractures in traumatic damage of the optic nerve].

Ten patients with orbital fractures and optic nerve trauma are reported. Fractures of the optic canal could be demonstrated by computed tomography in six cases and fractures of the orbital apex in another three cases. Surgical decompression of the optic canal was performed in seven cases. Computed tomography enhanced decision for surgery in cases of intraorbital haematoma with exophthalmus and narrowing of the canal by bony fragments, especially in those patients presenting with incomplete or progressive visual disturbance.

Emergencies↗
PubMed1989

Computerized tomography after internal fixation of the spine.

32 patients with internal fixation of the spine were postoperatively examined by computerized tomography. Details of metallic osteosynthetic material were demonstrated in all our cases. Bony structures were well defined in 27 patients, whereas soft tissue imaging was degraded by scattering artifacts in 14 of 20 examinations. Application of intrathecal contrast medium, however, was helpful for the evaluation of intraspinal soft tissues. Involvement of extraspinal soft tissues could be interpreted on the basis extent of vertebral osseous destruction.

Fracture Fixation, Internal↗
PubMed1989

Molecular cloning of two west African human immunodeficiency virus type 2 isolates that replicate well in macrophages: a Gambian isolate, from a patient with neurologic acquired immunodeficiency syndrome, and a highly divergent Ghanian isolate.

Human immunodeficiency virus type 2 (HIV-2)-related viruses were isolated from a Gambian dying of exclusively neurological disease (HIV-2D194) and from an asymptomatic Ghanian (HIV-2D205). Both strains exhibited properties of HIV-1 biological subtype c: they grew slowly and induced few or no syncytia but eventually produced high levels of particle-associated reverse transcriptase in cultures of fresh peripheral blood lymphocytes, and they established stable infection of T-lymphoma (HUT-78) and monocytic (U937) cell lines. Each produced even higher levels of reverse transcriptase when fresh human monocytes/macrophages were used as target cells. The viruses were molecularly cloned after a single passage in culture, in order to minimize in vitro selection of subtypes present in vivo. Restriction-site analysis showed heterogeneity within each isolate. Nucleotide sequence analysis of a portion of the HIV-2D194 genome revealed that it is a member of the prototypic HIV-2 family, displaying 13% divergence versus HIV-2ROD and HIV-2NIHZ, as compared to 9% divergence between HIV-2ROD and HIV-2NIHZ. In contrast, HIV-2D205 is the most highly divergent HIV-2 strain yet described: it is equidistant in relation between the known HIV-2 strains and the simian immunodeficiency virus isolates from rhesus macaque monkeys (23-25% divergence).

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Computed tomographic follow-up of cranio-cerebral injuries in children].

38 children with moderate and severe head injuries had CT follow-ups. On initial scans combined lesions dominated over diffuse (diffuse swelling, subarachnoid haemorrhage) and focal lesions (focal swelling, contusions). Contusion showed up until the 6th day after the accident. Two cases of focal lesions could be demonstrated only after intravenous contrast. Up to 40% of the children developed hypodense extracerebral accumulations. Long-term CT follow-ups showed ventricular (84%) and sulcal enlargement (63%) as well as hypodense parenchymal lesions (50%). Combined and diffuse lesions showed a correlation of initial scans and long-term follow-up which could not be demonstrated in case of focal lesions.

Adolescent↗