Methods for the separation of hydraulic retention time and solids retention time in the application of photosynthetic microorganisms in photobioreactors: a review.

Photosynthetic microorganisms have a wide range of biotechnical applications, through the application of their versatile metabolisms. However, their use in industry has been extremely limited to date, partially because of the additional complexities associated with their cultivation in comparison to other organisms. Strategies and developments in photobioreactors (PBRs) designed for their culture and applications are needed to drive the field forward. One particular area which bears examination is the use of strategies to separate solid- and hydraulic-residence times (SRT and HRT), to facilitate flow-through systems and continuous processing. The aim of this review is to discuss the various types of PBRs and methods which are currently demonstrated in the literature and industry, with a focus on the separation of HRT and SRT. The use of an efficient method of biomass retention in a PBR may be advantageous as it unlocks the option for continuous operation, which may improve efficiency, and improve economic feasibility of large-scale implementation of photosynthetic biocatalysts, especially where biomass is not the primary product. Due to the underexplored nature of the separation of HRT and SRT in reactors using photosynthetic microorganisms, limited literature is available regarding their performance, efficiencies, and potential issues. This review first introduces an overview into photosynthetic microorganisms cultivated and commonly exploited for use in biotechnological applications, with reference to bioreactor considerations specific to each organism. Following this, the existing technologies used for the separation of HRT and SRT in PBRs are explored. The respective advantages and disadvantages are discussed for each PBR design, which may inform an interested bioprocess engineer.

In search of more representative cervical cytology. A preliminary prospective study.

Non-representative cervical smears represented 26.5% of the 105,165 smears screened by the cytology laboratory at Tygerberg Hospital during the period 1986 - 1987. This figure varied from 21% to 41% depending on the skill of the performer. In an effort to secure more representative smears a preliminary prospective study was conducted to ascertain the value of a variety of devices (Ayre wooden spatula, saline-soaked cotton-wool swab, Cytobrush). Initially these devices were employed by one specific clinician and subsequently by a variety of medical personnel. This study proved that in the hands of all the personnel endocervical cells were present in all smears taken by the Cytobrush technique, obviating the need for repeat smears. The combination of an ectocervical scrape by an Ayre wooden spatula with an endocervical Cytobrush smear applied to one slide should result in more representative smears at screening. The resultant higher cost should be offset by minimising repeat smears.

High risk malignant gestational trophoblastic disease: experience with triple chemotherapy (MAC) in Third World circumstances.

Fifty-seven patients with malignant gestational trophoblastic disease (GTD) were treated by the Gynecologic Oncology Unit of the Tygerberg Hospital, Parowvallei, RSA, between 1977 and 1986. Treatment was primarily with triple chemotherapy (MAC) followed by citrovorum factor. The total remission rate in the 23 patients with high risk malignant GTD was 78.3% but in the 16 patients categorized as poor prognosis metastatic disease the remission rate dropped to 68.8%. The third world background in the majority of our patients, the poor general health, and the language barrier indirectly influenced the management of these patients. Psychological problems were evident in 60.9% of our patients. This often resulted in poor patient compliance which adversely influenced the outcome of the disease.

A cost-effective but safe protocol for the staging of invasive cervical carcinoma in a third world country.

The treatment and prognosis of invasive cervical carcinoma depends on proper clinical staging. The prestaging investigations are time-consuming and costly and 3rd world countries find it difficult to adhere to 1st world protocols. In the search for a more cost-effective but safe protocol for pre-treatment investigation the analysis of some of the special investigations performed on a total of 903 patients with invasive cervical carcinoma have proven beyond doubt that some of these investigations can be omitted without harming the patient. The Gynecologic Oncology Unit of the Tygerberg Hospital R.S.A. propose such a cost-effective protocol provided some criteria are strictly adhered to in safe-guarding proper health care.

Ultrasonographic criteria for the conservative management of antenatally diagnosed fetal ovarian cysts.

Routine antenatal ultrasonography at regular intervals will detect fetal ovarian cysts. Before the era of ultrasound, the attending physician was unaware of the presence of these cysts. It is therefore imperative that a protocol for the management of asymptomatic, antenatally diagnosed ovarian cysts be developed. The vast majority of these cysts are benign and functional; laparotomy during the neonatal period is not only unnecessary but may be harmful. In a prospective study undertaken at Tygerberg Hospital, Parowvallei, South Africa, six ultrasound criteria were drawn up for the safe, conservative management of these neonates. Adherence to these criteria enabled us to manage five of seven neonates conservatively. Laparotomy in one neonate showed a benign functional ovarian cyst. Retrospectively, this case should have been managed conservatively. In the remaining neonate a laparotomy for an acute abdomen demonstrated torsion of an ovarian cyst, emphasizing the necessity for adequate follow-up.

Radioisotope bone scanning for the detection of occult bony metastases in invasive cervical carcinoma.

Radioisotope bone scans to search for occult skeletal metastases at initial staging were obtained in 540 patients with invasive cervical carcinoma admitted to the Gynecological Oncology Unit of the Tygerberg Hospital over a 36-month period. Positive scans were reported in 55 (10.2%) patients but subsequent radiographic examination revealed that of these, 43 were false positive. The 11 patients with bony metastases were all initially classified as Stage III or IV disease irrespective of the bone scan and the positive scans influenced the clinical staging in only 6 (1.1%) patients. All the bone scans in the 210 patients with clinical Stage I or II disease were negative. Bone scanning does not seem warranted at initial staging in Stage I or II invasive cervical carcinoma.

Immune deficiency and invasive carcinoma of the vulva in a young woman: a case report.

A case report on a 26-year-old virgo intacta with a long standing history of pruritus vulvi, obstructive pulmonary disease, and chronic diarrhea presenting with an invasive squamous carcinoma of the vulva in association with chronic malabsorption and T-lymphocyte deficiency.

Immature teratoma of the ovary with gliomatosis peritonei. A case report.

Gliomatosis peritonei is a rare complication of immature teratoma of the ovary and should not be confused with metastatic ovarian carcinoma. Treatment depends on the histological grading of the gliomatous lesions. All grades, except grade 0, qualify for adjuvant chemotherapy. Repeated laparotomies for cytological sampling and the removal of tumour are essential. A 16-year-old Ovambo nulligravida presenting with gliomatosis peritonei was apparently cured after 5 laparotomies for removal of tumour and 13 courses of combination chemotherapy.

The value of cytological examination of the urine in the staging of invasive carcinoma of the cervix. A prospective study.

During the period July 1976 - December 1978 midstream urine specimens were collected from all new patients with invasive cervical carcinoma admitted to Tygerberg Hospital, Parowvallei, CP. All specimens were cytologically screened to try and establish any correlation between the cytological result an the clinical staging. A very high proportion (24.2%) of specimens unsuitable for screening and unacceptable false-negative and false-positive rates forced us to abandon this prospective study. From January 1979 to July 1980 the study was repeated on catheter specimens of urine. The final analysis of the second series revealed that a catheter specimen had definite advantages, but a detection rate of only 37.5% and a false-negative rate of 62.5% forced us to conclude that urinary cytological examination is at present too inaccurate to be of any value in the staging of invasive cervical carcinoma.

Routine investigations in the clinical staging of invasive carcinoma of the cervix. A critical evaluation.

From July 1976 to December 1978 invasive carcinoma of the cervix in 369 new patients at Tygerberg Hospital, Parowvallei, CP, was classified into stages according to the International Federation of Gynaecology and Obstetrics (FIGO) classification. Most of these patients underwent routine intravenous pyelography, cystoscopy, and skeletal and chest radiography, the results of which were analysed in relation to the stage of the disease to decide whether all these investigations are needed in every case. It is concluded that under certain circumstances cystoscopy and skeletal radiography may be omitted with safety in stage I and stage II disease.

The incomplete cone in carcinoma in situ of the cervix: A prospective study in a developing country.

The diagnostic procedures and treatment of carcinoma in situ and severe dysplasia of the cervix are becoming more conservative. In a developing country special problems make such an approach more hazardous. During a 15-month period the diagnosis in 25 of 206 patients (12,1%) with a smear positive for carcinoma in situ could not be confirmed histologically at Tygerberg Hospital. A prospective study of 147 cases (71,4%) in which the diagnosis was confirmed revealed that they were mostly young patients of relatively high gravidity. The difficulty of assessing the completeness of a cervical cone and of evaluating a postconization smear is confirmed. The danger of a too conservative approach in our patients is confirmed by the fact that only 8,2% of patients came for regular follow-up examinations and that 34,7% did not return for follow-up smears. The high incidence of total hysterectomy (51,7%) as the definitive form of treatment is defended, and a more conservative future approach of confirming the diagnosis and reducing the incidence of cervical conization is suggested.

Cervical cytologic screening among females with nongynecologic hospital admissions.

Routine vaginal cytologic screening in nongynecologic admissions to Tygerberg Hospital revealed a detection rate for pelvic neoplasia of 9.3/1000 patients. Of these, 22 (16%) did not derive any benefit from this program because of the severity of the primary extrapelvic disease. However, 57% of those detected were still in the in situ stage and should have a 100% 5-year survival. The treatment was considered to be complete in 54.4% of the cases. As this service is performed by nursing personnel as part of their daily duty, this program seems to be a sound economic proposition.