PubMed Health⌕ Search

Biomedical subjects

L R Mello

Publications and source records attributed to L R Mello.

16 recordsLinked to original sources
PubMed2001

Thoracic spine arachnoid ossification with and without cord cavitation. Report of three cases.

Thoracic spine arachnoid ossification is a relatively rare disease that affects mainly women and causes sensory, motor, and sphinctal symptoms associated with inferior limb pain. Based on three cases, the authors comment on pathogenic and surgery-related aspects of the disease. The patient in Case 1 was followed over the course of 23 years. Spinal cavitation is highlighted in Case 2, and yellow, gross, half-ring ossification is described in Case 3. Calcium deposits usually occur in the middle and lower thoracic spine where the majority of trabeculated arachnoid cells are located. Operative treatment does not interrupt the ossification process, which continues over time, causing progressive deterioration in the patient. Spinal cavitation can occur due to spinal cord tethering, stretching, and central cord edema formation, accompanied by cerebrospinal fluid blockage and pulse pressure changes. The results of surgical intervention are poor, offering short-term recovery with later deterioration. Multiple pathogenic factors are involved in this clinical syndrome including metabolic changes.

Adult↗
PubMed2001

[Use of lyophilized cellulose in peripheral nerve lesions with loss of substance].

Lyophilized cellulose was analysed to verify the degree of inflammatory reaction and axon realignment in the sciatic nerve after loss of neural substance. Ten mongrel dogs were divided into: Group 1 - 1 cm section of sciatic nerve which was replaced at lesion site; Group 2 nerve section without fragment replacement. The section site was involved with lyophilized cellulose. Group 3 -1 cm fragment section sutured epineurally. Motor response started at eighth week. Moderate fibrotic reaction to cellulose was seen in Group 1 and 2 animals. Groups 1 and 3 showed coaptation between the nerve and nerve graft with ongoing axons. In Group 2, 1 dog showed regrowth of axons through the empty space. It was concluded that lyophilized cellulose caused moderate fibrous reaction when implanted in peripheral nerve lesions with loss of substance; it can act as envelop protection in those lesions mainly if a neural graft is inserted.

Animals↗
PubMed1998

[Hemostatic and structural effects of the lyophilized cellulose sponge].

Hemostatic effects of oxidized cellulose (Surgicel) are well known. Based on a possible similar effect of a sponge obtained after lyophilization of biosynthetic cellulose, two different experimental studies were planned. Phase I-Pieces of cellulose sponge were inserted into small provoked cortical wounds of twelve dogs. The time elapsed to obtain bloodstill after cortical damage and application of cellulose was observed in every dog, searching to detect any possible hemostatic effect of the material. The animals were sacrificed after 7, 30 and 90 days. An average time of 1 minute was elapsed until bleeding control was achieved. No clinical adverse effect was noticed. Microscopy showed histiocytic and mild foreign body reaction at 7 days, which diminished at 30 days. Almost no reaction surrounded the implant at 90 days. Lyophilized cellulose has a peculiar eosinophilic appearance, composed by thin irregular filaments which diminished their thickness with the time. At 90 days only sparse irregular cellulose filaments could be detected. Phase II-Small equal sponge fragments were inserted in the liver of twelve rats and observed 7, 30 and 90 days. At autopsy, small peritoneal adhesions were noticed at 30 and 90 days. Microscopy showed intense histioplasmocytic and foreign body reaction in all animals mainly at 7 days. In two animals, refringent intracellular cellulose particles were evident inside giant foreign body cells after 90 days. This fact evidences that cellulose can be reabsorbed by phagocytic phenomena when implanted in mammalians. A comparative group with other hemostatic material and the same method must be done to clarify the issue of hemostatic effects of this membrane.

Animals↗
PubMed1997

Frequency of the different mutations causing spinocerebellar ataxia (SCA1, SCA2, MJD/SCA3 and DRPLA) in a large group of Brazilian patients.

Spinocerebellar ataxia type 1 (SCA1), spinocerebellar ataxia type 2 (SCA2) and Machado-Joseph disease or spinocerebellar ataxia type 3 (MJD/SCA3) are three distinctive forms of autosomal dominant spinocerebellar ataxia (SCA) caused by expansions of an unstable CAG repeat localized in the coding region of the causative genes. Another related disease, dentatorubropallidoluysian atrophy (DRPLA) is also caused by an unstable triplet repeat and can present as SCA in late onset patients. We investigated the frequency of the SCA1, SCA2, MJD/SCA3 and DRPLA mutations in 328 Brazilian patients with SCA, belonging to 90 unrelated families with various patterns of inheritance and originating in different geographic regions of Brazil. We found mutations in 35 families (39%), 32 of them with a clear autosomal dominant inheritance. The frequency of the SCA1 mutation was 3% of all patients; and 6% in the dominantly inherited SCAs. We identified the SCA2 mutation in 6% of all families and in 9% of the families with autosomal dominant inheritance. The MJD/SCA3 mutation was detected in 30% of all patients; and in the 44% of the dominantly inherited cases. We found no DRPLA mutation. In addition, we observed variability in the frequency of the different mutations according to geographic origin of the patients, which is probably related to the distinct colonization of different parts of Brazil. These results suggest that SCA may be occasionally caused by the SCA1 and SCA2 mutations in the Brazilian population, and that the MJD/SCA3 mutation is the most common cause of dominantly inherited SCA in Brazil.

Adolescent↗
PubMed1997

Duraplasty with biosynthetic cellulose: an experimental study.

In the search for a new synthetic substitute for the dura mater, the authors conducted a research study using 32 mongrel dogs divided into three groups. Group I animals (21 dogs) underwent a right-sided parietooccipital craniotomy and substitution of two 1-cm pieces of dura mater by two different grafts: one piece of biosynthetic cellulose (50 mu thick) and one fragment of temporal fascia. The animals were observed for 30, 90, or 180 days. Group II animals (five dogs) underwent a somewhat larger craniotomy, removal of a 2-cm piece of dura mater, and lesioning of the cortex made by a thin sharp forceps, which caused bleeding that was controlled by application of a thin film of cellulose (10 mu thick). Duraplasty was performed using a 50-mu-thick cellulose membrane to complete the procedure and the animals were observed over a period of 270 days. Group III animals (six dogs) underwent smaller (1-cm diameter) bilateral parietal craniectomy, which included additional covering of the dura on the left side with 50-mu-thick cellulose and a suture of temporalis muscle. This group was observed for 40, 60, 80, or 120 days. Transient mild clinical symptoms were observed during the early postoperative period. At autopsy, macroscopic examination demonstrated good acceptance of the grafts with few and moderate extradural fibrosis, which caused adherence of the implants to the bone fragment. No adherence to the cortex was observed. Microscopic examination demonstrated absence of graft adherence to the cortical surface even when the cortex was injured. The cellulose was enveloped by two layers of connective tissue, the external layer being thicker than the internal one. Cellulose fibers increased in thickness over time until 30 days and then decreased in thickness until 270 days. This decrease in thickness between 30 to 270 days was statistically significant (p < 0.05). The physical properties of biosynthetic cellulose and the low cellular reaction to its implantation qualify this material as a dural substitute. Additional long-term studies must be undertaken to complete this report.

Animals↗
PubMed1992

[Extradural hematoma: comparative radiological study between comatose and non-comatose patients].

A series of 129 patients harbouring extradural hematomas was analysed considering the neurological state immediately before operation as the most consistent variable. Seventy eight patients were considered to be comatose (Group I) and 51 were noncomatose. Among the comatose group, 30 were investigated with computerized tomography (23.3% mortality, 50% good results), 31 were submitted to angiography (48.3% mortality, 38.7% good results), and 17 were operated based on the neurological examination and skull radiography (47% mortality, 35.2% good results). The presence or absence of skull fracture and the density of hematoma did not change the final outcome. Associated intracranial lesions increased the mortality and lowered the good results in both groups. Frontal hematomas (10 cases) in the comatose group were associated with high mortality (52.6%) due to bad neurological state (Glasgow 3-5) and to isolated or multiple intracranial associated lesions (6 patients).

Brain Injuries↗
PubMed1985

[Infantile metachromatic leukodystrophy in twins].

The authors report two cases of infantile metachromatic leucodystrophy in monozygotic female twins, born from a second cousin marriage (f = 1/32). The zygosity was determined by means of obstetrics and genetics marker findings.

Child, Preschool↗
PubMed1982

[Infections in neurosurgery].

The incidence of infection in neurological surgery is analysed by the author due to an almost epidemic occurrence of wound contamination by staphylococcus aureus in the year 1977. A brief review of the literature data is presented concerning the factors related to the patient's own immunity, the operative wound and the hospital environment, that may cause infection. Based on 733 operations done in a period of 50 months the author exposes the modifications installed for avoiding the infective sources. Antiseptic technic and surgical tactic were modified during the three steps of this study. In the first two periods, each of one lasting 17 months, the infection rates for clean surgical procedures were 10,3 and 6,7% respectively. By the last 15 months, when topical oxacyllin powder was added, the infection rate dropped to 0,6%. The general infection rates for clean, clean with implants, clean-contaminated and contaminated operations, during the three periods were 7,08, 6,8 and 3,4%. A critical review of the data concerning to systemic and topical prophylactic antibiotic therapy is followed by comments on the basis of the technical changes made in this clinical study. Shaving close to the operation, dry preparation of the scalp flap and muscle, use of only bipolar coagulation, restrict use of serum irrigation during the epidural stages of the operation an topical use of oxacillin powder before wound closure were the main technical modification introduced.

Anti-Bacterial Agents↗
PubMed1978

[Parasagittal meningioma simulating an extracerebral mass. Report of a case].

The case of a fronto-parietal parasagital "in plaque" meningioma which growed mainly in the subdural space is reported. The atipical angiographic picture of a subdural hematoma is described with comments on the mechanisms that occasioned this radiological appearance. The rarity of this finding and the need of angiographycal study of both internal and external carotid systems by the intracranial meningiomas are emphasized.

Aged↗
PubMed1977

[Idiopathic arterial occlusive disease (moyamoya); report of 4 cases].

Four cases of the occlusive arterial disease "moyamoya" type, are reported with comments on the clinical, roentgenological and embriological aspects. The clinical onset in all four cases was of isquemic type, in spite of different ages (2 adult male, one young adult female, 1 child female). Some particular symptoms are analysed, mainly the constant complaint of episodes in which the patient is, suddendly, extremely tired. The causes of this episodes are thought to be due to suddendly lowering of the cerebral perfusion in the disease. The importance of the radiological appearance is emphasyzed. The plain roentgenographic films, the site of the occlusion, the associated vascular malformations, the collateral circulation and the site of the vascular nest, are discussed. Some embriologic aspects of the etiology including the variable time onset of the pathologic process are also discussed.

Adult↗
PubMed1975

[Comparative radiological study between spasmodic torticollis and Parkinson's disease. Notes on the etiology of spasmodic torticollis].

The comparative clinic-radiological study between 45 patients with spasmodic torticollis and the same amount of patients with either essential Parkinsonism or tremor is reported. The study was based mainly on the alterations verified by plain roentgenograms and pneumoencephalography. The comparison between the findings obtained on both groups led the authors to conclude that neuroradiological aspects have statiscally no value in clarifying the etiology of the spasmodic torticollis.

Adolescent↗
PubMedDate not supplied

[Devic disease: a case report]

OBJECTIVE: To report a case of Devic disease, emphasizing its diagnosis, in addition to reviewing the medical literature. DESCRIPTION: Male, six-year-old patient suddenly developed weakness in lower limbs, with resolution during hospital stay. However, as the weakness disappeared, loss of vision occurred. The symptoms were reverted after the use of prednisone. COMMENTS: The diagnostic and therapeutic approach was similar to that used in other cases reported by different reference centers. In other words, clinical diagnosis and prednisone therapy were used, with the complete improvement of symptoms. However, there is still some controversy surrounding its etiology and relationship with other demyelinating diseases, such as multiple sclerosis.

Journal Article↗