Electrostatically Interactive Injectable Hydrogels for Drug Delivery

BACKGROUND: Several injectable hydrogels have been developed extensively for a broad range of biomedical applications. Injectable hydrogels forming in situ through the change in external stimuli have the distinct properties of easy management and minimal invasiveness, and thus provide the advantage of bypassing surgical procedures for administration resulting in better patient compliance. METHODS: The injectable in situ-forming hydrogels can be formed irreversibly or reversibly under physiological stimuli. Among several external stimuli that induce formation of hydrogels in situ, in this review, we focused on the electrostatic interactions as the most simple and interesting stimulus. RESULTS: Currently, numerous polyelectrolytes have been reported as potential electrostatically interactive in situ-forming hydrogels. In this review, a comprehensive overview of the rapidly developing electrostatically interactive in situ-forming hydrogels, which are produced by various anionic and cationic polyelectrolytes such as chitosan, celluloses, and alginates, has been outlined and summarized. Further, their biomedical applications have also been discussed. CONCLUSION: The review concludes with perspectives on the future of electrostatically interactive in situ-forming hydrogels.

Thermoresponsive and Biodegradable Amphiphilic Block Copolymers with Pendant Functional Groups

BACKGROUND: To develop the biodegradability and thermoresponsive hydrogel, in this work we designed a pendant-functionalized, thermoresponsive, amphiphilic block copolymer. METHODS: Methoxy poly(ethylene glycol) (MPEG)-b-[poly(ε-caprolactone)-ran-poly(ε-caprolactone-3-one)-ran-polylactic acid] (MCL) and (MPEG-b-[PCL-ran-POD-ran-PLA]) [MCL-(CO)] block copolymers were prepared by ringopening polymerization of ε-caprolactone, OD and lactide monomers. The subsequent derivatization of MCL-(CO) provided MPEG-b-[PCL-ran-poly(ε-caprolactone-3-COOH)-ran-PLA] [MCL-(COOH)] with COOH pendant groups and MPEG-b-[PCL-ran-poly(ε-caprolactone-3-NH2)-ran-PLA] [MCL-(NH2)] with NH2 pendant groups. RESULTS: The measured segment ratios of MCL-(CO), MCL-(COOH), and MCL-(NH2) agreed well with the target ratios. The abundances of the COOH and NH2 groups in the MCL-(COOH) and MCL-(NH2) copolymers were determined by 1H- and 13C-nuclear magnetic resonance spectroscopy, and agreed well with the target abundances. MCL-(CO), MCL-(COOH), and MCL-(NH2) formed homogeneous, white, opaque emulsions at room temperature. Rheological analysis of the block copolymer suspensions indicated a solution-to-hydrogel phase transition as a function of temperature. The solution-to-hydrogel phase transitions and the biodegradation of MCL-(CO), MCL-(COOH), and MCL-(NH2) were affected by varying the type (ketone, COOH, or NH2) and abundance of the pendant groups. CONCLUSION: MCL-(CO), MCL-(COOH), and MCL-(NH2) with ketone, COOH, and NH2 pendant groups showed solution-to-hydrogel phase transitions and biodegradation behaviors that depended on both the type and number of pendant groups.

Effect of Drug Carrier Melting Points on Drug Release of Dexamethasone-Loaded Microspheres

Here, we examined the effect of melting point of drug carriers on drug release of dexamethasone (Dex)-loaded microspheres. We prepared poly(L-lactide-ran-ε-caprolactone) (PLC) copolymers with varying compositions of poly(εcaprolactone) (PCL) and poly(L-lactide) (PLLA). As the PLLA content increased, the melting points of PLC copolymers decreased from 61 to 43 ℃. PLC copolymers in vials solubilized at 40–50 ℃ according to the incorporation of PLLA into the PCL segment. Dexamethasone (Dex)-loaded PLC (MCxLy) microspheres were prepared by the oil-in-water (O/W) solvent evaporation/extraction method. The preparation yields were above 70%, and the mean particle size ranged from 30 to 90 µm. The MC(x)L(y) microspheres also showed controllable melting points in the range of 40–60 ℃. Dex-loaded MC(x)L(y) microspheres showed similar in vitro and in vivo sustained release patterns after the initial burst of Dex. The in vitro and in vivo order of the Dex release was MC₈₀L₂₀>MC₉₀L₁₀>MC₉₅L₅, which agreed well with the melting point order of the drug carrier. Using in vivo fluorescence imaging of fluorescein (FI)-loaded microspheres implanted in animals, we confirmed the sustained release of FI over an extended period. In vivo inflammation associated with the PLC microsphere implants was less pronounced than that associated with Poly(lactide-co-glycolide) (PLGA). In conclusion, we successfully demonstrated that it is possible to control Dex release using Dex-loaded MC(x)L(y) microspheres with different melting points.

The Expression Profile of Angiotensin System on Thawed Murine Ovaries

Freezing and thawing is one of the most widely used tissue engineering techniques for the preservation of ovaries. Many cells and tissues demonstrate changes in functional gene expression after thawing. Several studies have reported the important roles of angiotensin (AT) system during the ovarian follicular growth. AT system consists of ATII, and ATII receptors type I (ATII-RI) and type II (ATII-RII). However, little is known whether frozen-thawed ovaries show any alteration of AT system member gene expression when treated with survival-enhancing factors. We aimed to investigate whether mass freezing and thawing with or without the use of Rho-associated kinase (ROCK) inhibitors up- or down-regulate the expression of ATII, ATII-RI, and ATII-RII genes on frozen-thawed ovarian tissues. Significant changes in the expression of ATII, ATII-RI, and ATII-RII genes were observed on thawed ovaries when compared to fresh control. The treatment with ROCK inhibitors did not significantly alter their expression. In conclusion, freezing and thawing of ovarian tissue may affect the mRNA expression levels of intra-ovarian AT system genes, and modulation of ROCK inhibitor activity may not regulate AT system on the frozenthawed ovarian tissue.

Benign Lymphoepithelial Cyst of the Parotid Gland as an Initial Manifestation of Human Immunodeficiency Virus Infection / 대한내과학회지

Benign lymphoepithelial cysts are rare, and are associated with swelling of the salivary glands (usually the parotid gland). The cytopathological features include lymphoid hyperplasia with an epithelial component, exhibiting cystic and proliferative changes. Development of a benign lymphoepithelial cyst commonly precedes acquisition of acquired immunodeficiency syndrome, but may also be the initial clinical manifestation of human immunodeficiency virus (HIV) infection. A 43 year-old male presented with a slowly growing multilocular cystic mass in his right cheek. Computed tomography of the neck revealed a well-circumscribed cystic lesion in the bilateral parotid glands. A provisional diagnosis of a benign lymphoepithelial cyst associated with HIV infection was made, and Western blotting confirmed the HIV infection. Three months after initiation of antiretroviral therapy, the parotid swelling was completely resolved. We report this case to suggest that clinicians should consider the possibility of HIV infection when patients present with benign lymphoepithelial cysts of the parotid gland.

Anatomic Feasibility of Posterior Cervical Pedicle Screw Placement in Children : Computerized Tomographic Analysis of Children Under 10 Years Old

OBJECTIVE: To evaluate the anatomical feasibility of 3.5 mm screw into the cervical spine in the pediatric population and to establish useful guidelines for their placement. METHODS: A total of 37 cervical spine computerized tomography scans (24 boys and 13 girls) were included in this study. All patients were younger than 10 years of age at the time of evaluation for the period of 2007-2011. RESULTS: For the C1 screw placement, entry point height (EPH) was the most restrictive factor (47.3% patients were larger than 3.5 mm). All C2 lamina had a height larger than 3.5 mm and 68.8% (51/74) of C2 lamina had a width thicker than 3.5 mm. For C2 pedicle width, 55.4% (41/74) of cases were larger than 3.5 mm, while 58.1% (43/74) of pedicle heights were larger than 3.5 mm. For pedicle width of subaxial spine, 75.7% (C3), 73% (C4), 82.4% (C5), 89.2% (C6), and 98.1% (C7, 1/54) were greater than 3.5 mm. Mean lamina width of subaxial cervical spine was 3.1 (C3), 2.7 (C4), 2.9 (C5), 3.8 (C6), and 4.0 mm (C7), respectively. Only 34.6% (127/370) of subaxial (C3-7) lamina thickness were greater than 3.5 mm. Mean length of lateral mass for the lateral mass screw placement was 9.28 (C3), 9.08 (C4), 8.81 (C5), 8.98 (C6), and 10.38 mm (C7). CONCLUSION: C1 lateral mass fixation could be limited by the morphometrics of lateral mass height. C2 trans-lamina approach is preferable to C2 pedicle screw fixation. In subaxial spines, pedicle screw placement was preferable to trans-lamina screw placement, except at C7.

Early Surgical Treatment of Pronator Teres Syndrome

We report a rare case of pronator teres syndrome in a young female patient. She reported that her right hand grip had weakened and development of tingling sensation in the first-third fingers two months previous. Thenar muscle atrophy was prominent, and hypoesthesia was also examined on median nerve territory. The pronation test and Tinel sign on the proximal forearm were positive. Severe pinch grip power weakness and production of a weak "OK" sign were also noted. Routine electromyography and nerve conduction velocity showed incomplete median neuropathy above the elbow level with severe axonal loss. Surgical treatment was performed because spontaneous recovery was not seen one month later.

Invasions and Metastases of Facial and Neck Skin by Head and Neck Cancer / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: This study was designed to review the incidence of skin involvement in the head and neck cancer. We also reviewed its pattern, treatment results, and prognostic significance of skin invasion and metastases. MATERIALS AND METHODS: We carried out an retrospective evaluation of 41 patients who required resection of the facial or neck skin during surgery for their head and neck cancer in the last ten years. Patients with head and neck skin cancer were excluded from this study. Patients who developed skin involvement were evaluated with regard to the primary origin of tumor, the tumor stage, and the pattern of skin involvement, treatment and outcome. The cases were classified into four groups: firstly, a group with the presence of skin scar made by previous biopsy; secondly, a group with tumor fixed to skin; thirdly, a group with skin resected with a sufficient resection marginal, and lastly a group with gross involvement of skin by tumor. RESULTS: Among 41 patients who required resection of the skin, patients with skin invasion were noted in 24 cases. Only one out of four cases of the biopsy group had skin involvement whereas a half of the fixed group had skin invasion. For the marginal group, only two cases had invasion of skin. The treatment result of patients with skin involvement had poor prognosis compared to patients without skin involvement. In particular, patients with skin metastasis had extremely poor survival. CONCLUSIONS: Skin involvement in the head and neck cancer indicates a poor prognosis, and should not be considered for surgery.

A Case of Congenital Vestibular Anomaly with Direction Changing Positional Nystagmus / 대한이비인후과학회지

Direction changing positional nystagmus (DCPN) is defined as a nystagmus that changes its direction with different head and body positions. In the past, it was usually thought that DCPN was the sign of central vestibular system lesion. But recently, there have been some reports that DCPN definitely does not localize the site of lesion in the central vestibular pathway, and that it more often indicates a peripheral vestibular site. However, congenital vestibular dys- or hypoplasia was not reported as a cause of DCPN. Recently, we experienced a 17-year-old patient who had a vestibular dys- or hypoplasia and showed a transient geotrophic DCPN with a normal cochlea. We report that congenital vestibular dys- or hypoplasia can be one of the causes of DCPN and present its possible mechanism.

A Case of Malignant Fibrous Histiocytoma of the Pterygopalatine Fossa / 대한이비인후과학회지

Although there are some reports of malignant fibrous histiocytoma arising from the head and neck region, there has been no reports on the case originating from pterygopalatine fossa. We experienced a case of 29-year old male patient who visited our hospital with complaints of trismus, periorbital swelling and altered sensation on the left zygomatic area. On physical examination, he showed hypertrophic left middle turbinate, retracted ear drum, and swollen posterior wall of the nasopharynx. On computed tomography, he also showed a low density lesion originating from pterygopalatine fossa. Based on these findings, he was diagnosed with malignant fibrous histiocytoma originating from pterygopalatine fossa. and underwent radical maxillectomy, marginal mandibulectomy, radical neck dissection, and tracheotomy.

The Efficacy of Stellate Ganglion Block in the Treatment of Idiopathic Sudden Sensorineural Hearing Loss / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: A stellate ganglion block (SGB) induces vasodilatation in the head, neck, and upper extremities. Based on this principle, SGB has been widely used as one of the treatment modalities in sudden idiopathic sensorineural hearing loss (S-SNHL). However, until now, published data establishing the statistical significance of the effect of SGB has been slim. We conducted this study to find out the effect of SGB in the treatment of idiopathic S-SNHL and to find out the factors influencing the prognosis of the disease. MATERIALS AND METHODS: We reviewed the records of 221 patients seen in the past eight years between 1990 to 1997 who had an initial diagnosis of idiopathic S-SNHL and was admitted for treatment. One hundred twenty patients were treated with SGB and the other 101 patients were treated without SGB to use as a control group. RESULTS: The therapeutic result of SGB group was better than that of the control group. Especially, statistical difference was found in the following two subgroups; one in which the interval between the onset of disease and the initiation of treatment was from 8 to 28 days, and the other when the initial hearing loss was below 90 dB. CONCLUSION: We suggest that this study could be utilized as a standard of clinical treatment when SGB is performed.

Surgery for the Base of the Tongue Cancer in Conjunction with Supraglottic Partial Laryngectomy / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Cancer arising in the base of the tongue with extension to the supraglottic larynx or cancer of the epiglottis with extension to the base of the tongue require wider surgical approach than conventional supraglottic partial laryngectomy. This paper is to review techniques and postoperative results of mandibular swing approach for resection of the base of the tongue with supraglottic larynx. MATERIALS AND METHODS: We applied mandibular swing approach for three cases of the base of tongue cancer with significant extension to supraglottis. Two patients were stage T3 and the other was T4. RESULTS: In two patients, oral feeding without aspiration was possible with 5X6, 4X5 cm sized base of the tongue resection. Reconstruction was performed using primary repair between resected margin of the tongue and thyroid cartilage. In one case, an unexpected wide submucosal tumor extension to the hypopharynx was found, so a total glossolaryngectomy had to be performed. CONCLUSION: Resection of the base of the tongue beyond foramen cecum and primary repair may be possible without jeopardizing postoperative deglutition. Mandibular swing approach in conjunction with supraglottic partial laryngectomy was useful for the base of tongue cancer with supraglottic extension.

A Case of Hereditary Hemorrhagic Telangiectasia: Surgical Treatment with Modified Septodermoplasty / 대한이비인후과학회지

Hereditary hemorrhagic telangiectasia (HTT) or Rendu-Osler-Weber disease, identified nearly a century ago, is a familiar syndrome inherited by an autosomal dominant mode. It is characterized by recurrent epistaxis with multiple telangiectatic lesions on the mucosa and skin, basically capable of involving blood vessels in any part of the body. HTT is an important disease for otolaryngologists to familiarize with, because 90 percent of patients who experience epistaxis are referred to the department of otorhinolaryngology for its evaluation and treatment. Its occurence is not unusual in the western countries, but relatively rare in many Asian countries. We report a recent case of a 64-year-old male patient who had been suffering from GI bleeding, and experiencing recurrent epistaxsis for more than 30 years. His epistaxis was successfully treated with modified septodermoplasty.

Direction Changing Positional Nystagmus from Canalolithiasis and Cupulolithiasis of Lateral Semicircular Canal / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Clinical features of positional nystagmus may be different according to the etiology. Thus, efforts have been made to find out etiologies of various positional nystagmus. Until recently, positional vertigo was thought to arise from lesions of central nervous system. However, more recent investigations suggest that the peripheral lesion may be the main cause. Moreover, there have been some reports suggesting that directional changing positional nystagmus occurs due to canalolithiasis and cupulolithiasis of the lateral semicircular canal. The objectives of the study were to investigate the etiologies and clinical aspects of DCPN (direction changing positional nystagmus) from canalolithiasis and cupulolithiasis of the lateral semicircular canal, and to assess the effectiveness of the treatment. MATERIALS AND METHODS: Among 15 patients with DCPN, 9 patients showed nystagmus compatible with canalolithiasis of lateral semicircular canal and 6 patients with cupulolithiasis of lateral semicircular canal. Patients with cupulolithiasis and canalithiasis of the lateral semicircular canal did not respond to physical therapy for posterior semicircular canal. However, they were completely recovered by reposition maneuver for the lateral semicircular canal with or without using vibrator although 3 of them had recurred symptom. Four patients had BPPV of the posterior semicircular canal prior to the development of DCPN and 3 patients underwent the treatment of previous Meniere's disease. CONCLUSION: The patients with DCPN were due to canalithiasis and cupulolithiasis of the lateral semicircular canal, and physical therapy for lateral semicircular canal was rewarding.

Statistical Observation of In - Patients Referred to the Department of Dermatology / 대한피부과학회지

Statistical observation were made on 278 patients who were referred to the Department of Dermatology during their admission in Maryknoll Hospital from July 1, 1976 to June RO, 1978. This period begins one year before the initiation of the Medical Insurance Program on July 1, 1977 and extends to one year after(A period: 1976. 7. I~ 1977. 6. 3) B period: 1977.7.1~1978. 6. 30). The results are as follows: 1) Age distribution: The most frequent age group of both periods is the first decade(A period: 24.8%, B period: 22.1%) 2) Monthly distribution: There is no significant monthly difference 3) Distribution rate of every department: The most common department of both periods is Internal Medicine (A period: 26. 4%, B period: 32. 2%) 4) Distribution of diseases: The most frequent disease of both periods is Dermatitis and Eczema group(A period: RR.RY., B period: 80.2M) 5) Sex distribution: There is no significant sex difference(A period-M:F=l.5:1 B period.-M:F= 1.1:1) 6) Analysis of patients whose diagnosis of referred department is the same as diagnosis of the Department of Dermatology (1) Distribution rate of every department: The most common department is Internal Medicine (45. 8%) (2) Distribution of diseases: The most frequent disease of both periods is urticaria(A period: 33. 3%, B period: 25.0%) (3) Admission route: Admission via E-R was markedly decreased during B pericd (A perind: 50 %, B period: 16. 7%) 7) There is no significant change after the initiation of the Medical Insurance Program